Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a pro...Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a promising alternative to achieve low power consumption and nonvolatile electric control of magnetic properties.In this paper,a two-dimensional multiferroic van der Waals heterostructure OsCl_(2)/Sc_(2)CO_(2),which is composed of ferromagnetic monolayer OsCl_(2)and ferroelectric monolayer Sc_(2)CO_(2),is studied by first-principles density functional theory.The results show that by reversing the direction of the electric polarization of Sc_(2)CO_(2),OsCl_(2)can be transformed from a semiconductor to a half-metal,demonstrating a nonvolatile electrical manipulation of the heterostructure through ferroelectric polarization.The underlying physical mechanism is explained by band alignments and charge density differences.Furthermore,based on the heterostructure,we construct a multiferroic tunnel junction with a tunnel electroresistance ratio of 3.38×10^(14)%and a tunnel magnetoresistance ratio of 5.04×10^(6)%,allowing control of conduction states via instantaneous electric or magnetic fields.The findings provide a feasible strategy for designing advanced nanodevices based on the giant tunnel electroresistance and tunnel magnetoresistance effects.展开更多
The presence of a van Hove singularity(vHS)at the Fermi level can trigger magnetic instability by mediating a spontaneous transition from paramagnetic to magnetically ordered states.While electrostatic doping(typicall...The presence of a van Hove singularity(vHS)at the Fermi level can trigger magnetic instability by mediating a spontaneous transition from paramagnetic to magnetically ordered states.While electrostatic doping(typically achieved via ionic gating)to shift the vHS to the Fermi level provides a general mechanism for engineering such magnetism,its volatile nature often leads to the collapse of induced states upon gate field removal.Here,a novel scheme is presented for non-volatile magnetic control by utilizing ferroelectric heterostructures to achieve reversible magnetism switching.Using two-dimensional VSiN_(3),a nonmagnetic material with Mexican-hat electronic band dispersions hosting vHSs,as a prototype,it is preliminarily demonstrated that both electron and hole doping can robustly induce magnetism.Further,by interfacing VSiN_(3)with ferroelectric Sc_(2)CO_(2),reversible switching of its magnetic state via polarization-driven heterointerfacial charge transfer is achieved.This mechanism enables a dynamic transition between insulating and half-metallic phases in VSiN_(3),establishing a pathway to design multiferroic tunnel junctions with giant tunneling electroresistance or magnetoresistance.This work bridges non-volatile ferroelectric control with vHS-enhanced magnetism,opening opportunities for energy-efficient and high-performance spintronic devices and non-volatile memory devices.展开更多
Interlayer antiferromagnetic coupling,small magnetic anisotropy,and low air stability of the intrinsic magnetic topological insulator MnBi_(2)Te_(4)have been critical bottlenecks to the future application of the quant...Interlayer antiferromagnetic coupling,small magnetic anisotropy,and low air stability of the intrinsic magnetic topological insulator MnBi_(2)Te_(4)have been critical bottlenecks to the future application of the quantum anomalous Hall efect(QAHE)at zero magnetic feld.In this study,we propose a scheme to utilize capped sliding van der Waals materials to efectively modulate the magnetic and topological properties of MnBi_(2)Te_(4).Our results demonstrate that the h-BN/MnBi_(2)Te_(4)/h-BN heterostructure,constructed by sliding ferroelectric h-BN bilayer and MnBi_(2)Te_(4),not only realizes a transition from interlayer antiferromagnetic to ferromagnetic coupling but also signifcantly enhances the out-of-plane magnetism and air stability of MnBi_(2)Te_(4).Moreover,the above magnetic properties can be further improved by tuning the interlayer distance between h-BN and MnBi_(2)Te_(4).Additionally,the obtained band structures and topological properties clearly support that the h-BN/MnBi_(2)Te_(4)/hBN heterostructure can harbor the QAHE with a Chern number of C=1.This work provides a new and nonvolatile modulation approach to achieve high-temperature and high-precision QAHE at zero magnetic feld.展开更多
As a typical in-memory computing hardware design, nonvolatile ternary content-addressable memories(TCAMs) enable the logic operation and data storage for high throughout in parallel big data processing. However,TCAM c...As a typical in-memory computing hardware design, nonvolatile ternary content-addressable memories(TCAMs) enable the logic operation and data storage for high throughout in parallel big data processing. However,TCAM cells based on conventional silicon-based devices suffer from structural complexity and large footprintlimitations. Here, we demonstrate an ultrafast nonvolatile TCAM cell based on the MoTe2/hBN/multilayergraphene (MLG) van der Waals heterostructure using a top-gated partial floating-gate field-effect transistor(PFGFET) architecture. Based on its ambipolar transport properties, the carrier type in the source/drain andcentral channel regions of the MoTe2 channel can be efficiently tuned by the control gate and top gate, respectively,enabling the reconfigurable operation of the device in either memory or FET mode. When working inthe memory mode, it achieves an ultrafast 60 ns programming/erase speed with a current on-off ratio of ∼105,excellent retention capability, and robust endurance. When serving as a reconfigurable transistor, unipolar p-typeand n-type FETs are obtained by adopting ultrafast 60 ns control-gate voltage pulses with different polarities.The monolithic integration of memory and logic within a single device enables the content-addressable memory(CAM) functionality. Finally, by integrating two PFGFETs in parallel, a TCAM cell with a high current ratioof ∼10^(5) between the match and mismatch states is achieved without requiring additional peripheral circuitry.These results provide a promising route for the design of high-performance TCAM devices for future in-memorycomputing applications.展开更多
We have grown triply doped Mg:Fe:Mn:LiTaO3 crystals with near stoichiometry using the top seeded solution growth technique. The defect structure was investigated by infrared absorption spectra and Curie temperature. U...We have grown triply doped Mg:Fe:Mn:LiTaO3 crystals with near stoichiometry using the top seeded solution growth technique. The defect structure was investigated by infrared absorption spectra and Curie temperature. Using a blue laser as the source, excellent photorefractive properties were obtained. Nonvolatile holographic storage properties were investigated using the dual wavelength technique. We got a very high fixed diffraction efficiency and nonvolatile holographic storage sensitivity. The blue light has more than enough energy to excite holes of deep(Mn) and shallow(Fe) trap centers with the same phase, which enhance dramatically the blue photorefractive properties and the nonvolatile holographic storage. Mg2+ ion is no longer damage resistant at blue laser, but enhances photorefractive characteristics.展开更多
It has been suggested to use LiNbO3：Fe,Mn crystal for solving the problem of information volatility during the read-out process with all-optical facilities,but the minute order response time is far from the requireme...It has been suggested to use LiNbO3：Fe,Mn crystal for solving the problem of information volatility during the read-out process with all-optical facilities,but the minute order response time is far from the requirements for the real-time information processing.We present the nonvolatile holographic storage properties of LiNbO3：Hf,Fe,Mn.The response time is shortened to 5.0 s,and the sensitivity S is enhanced to 0.22 cm/J in this triply doped crystal.The experimental results show that the HfO2 doping threshold is 5.0 mol.%.Thus it seems that we have found a useful tetravalent dopant for LiNbO3：Fe,Mn that can obviously improve the nonvolatile holographic recording sensitivity.展开更多
A novel surface-type nonvolatile electric memory elements based on organic semiconductors CuPc and H2Pc are fabricated by vacuum deposition of the CuPc and H2Pc films on preliminary deposited metallic （Ag and Cu） el...A novel surface-type nonvolatile electric memory elements based on organic semiconductors CuPc and H2Pc are fabricated by vacuum deposition of the CuPc and H2Pc films on preliminary deposited metallic （Ag and Cu） electrodes. The gap between Ag and Cu electrodes is 3040μm. For the current-voltage （I-V） characteristics the memory effect, switching effect, and negative differential resistance regions are observed. The switching mechanism is attributed to the electric-field-induced charge transfer. As a result the device switches from a low to a high-conductivity state and then back to a low conductivity state if the opposite polarity voltage is applied. The ratio of resistance at the high resistance state to that at the low resistance state is equal to 120-150. Under the switching condition, the electric current increases -- 80-100 times. A comparison between the forward and reverse I-V characteristics shows the presence of rectifying behavior.展开更多
Polycrystalline LaCrO3（LCO） thin films are deposited on Pt/Ti/SiO2/Si substrates by pulsed laser deposition and used as the switching material to construct resistive random access memory devices. The unipolar resist...Polycrystalline LaCrO3（LCO） thin films are deposited on Pt/Ti/SiO2/Si substrates by pulsed laser deposition and used as the switching material to construct resistive random access memory devices. The unipolar resistive switching（RS） behavior in the Au/LCO/Pt devices exhibits a high resistance ratio of ~104 between the high resistance state（HRS） and low resistance state（LRS） and exhibits excellent endurance/retention characteristics.The conduction mechanism of the HRS in the high voltage range is dominated by the Schottky emission, while the Ohmic conduction dictates the LRS and the low voltage range of HRS. The RS behavior in the Au/LCO/Pt devices can be understood by the formation and rupture of conducting filaments consisting of oxygen vacancies,which is validated by the temperature dependence of resistance and x-ray photoelectron spectroscopy results.Further analysis shows that the reset current IR and reset power PR in the reset processes exhibit a scaling law with the resistance in LRS（R0）, which indicates that the Joule heating effect plays an essential role in the RS behavior of the Au/LCO/Pt devices.展开更多
Mg：Ru：Fe：LiN-bO3 crystals with various concentrations of MgO （in mole） and fixed content of RuO2 and Fe203 （in mass） are grown with the Czochralski method from the congruent melt. Their infrared transmission sp...Mg：Ru：Fe：LiN-bO3 crystals with various concentrations of MgO （in mole） and fixed content of RuO2 and Fe203 （in mass） are grown with the Czochralski method from the congruent melt. Their infrared transmission spectra are mea- sured and discussed to investigate the defect structure. With the increase of Mg2＋ concentration the blue nonvolatile holographic storage capability is enhanced. The nonvolatile holographic storage properties of dual-wavelength recording of Mg（7 mol%）：Ru：Fe：LiNbO3 nonvolatile diffraction efficiency, response time, and nonvolatile sensitivity reach 59.8%, 70 s, and 1.04 cm/J, respectively. Comparing Mg（7 mol%）：Ru：Fe：LiNbO3 with Ru：Fe：LiNbO3 crystal, the response time is shortened apparently. The nonvolatile diffraction efficiency and sensitivity are raised largely. The mechanism in blue photorefractive nonvolatile holographic storage is discussed.展开更多
Demands for low-energy microcontrollers have been increasing in recent years. Since most microcontrollers achieve user programmability by integrating nonvolatile (NV) memories such as flash memories for storing their ...Demands for low-energy microcontrollers have been increasing in recent years. Since most microcontrollers achieve user programmability by integrating nonvolatile (NV) memories such as flash memories for storing their programs, the large power consumption required in accessing an NV memory has become a major problem. This problem becomes critical when the power supply voltage of NV microcontrollers is decreased. We can solve this problem by introducing an instruction cache, thus reducing the access frequency of the NV memory. Unlike general-purpose microprocessors, microcontrollers used for real-time applications in embedded systems must accurately calculate program execution time prior to its execution. Therefore, we introduce a “transparent” instruction cache, which does not change the existing NV microcontroller’s cycle-level execution time, for reducing power and energy consumption, but not for improving the processing speed. We have conducted detailed microar chitecture design based on the architecture of a major industrial microcontroller, and we evaluated power and energy consumption for several benchmark programs. Our evaluation shows that the proposed instruction cache can successfully reduce energy consumption in a fairly wide range of practical NV microcontroller configurations.展开更多
IEEE J.Solid-State Circuits,2019,doi:10.1109/JSSC.2018.2884349Nonvolatile processor(NVP)is promising for energy-harvesting-powered internet-of-things(IoT)devices,owing to its unique capability to sustain computation p...IEEE J.Solid-State Circuits,2019,doi:10.1109/JSSC.2018.2884349Nonvolatile processor(NVP)is promising for energy-harvesting-powered internet-of-things(IoT)devices,owing to its unique capability to sustain computation progress over power outages.Recently.展开更多
Memristor is a newly found fourth circuit element for the next generation emerging nonvolatile memory technology. In this paper, design of new type of nonvolatile static random access memory cell is proposed by using ...Memristor is a newly found fourth circuit element for the next generation emerging nonvolatile memory technology. In this paper, design of new type of nonvolatile static random access memory cell is proposed by using a combination of memristor and complemented metal oxide semiconductor. Biolek memristor model and CMOS 180 nm technology are used to form a single cell. By introducing distinct binary logic to avoid safety margin is left for each binary logic output and enables better read/write data integrity. The total power consumption reduces from 0.407 mw (milli-watt) to 0.127 mw which is less than existing memristor based memory cell of the same CMOS technology. Read and write time is also significantly reduced. However, write time is higher than conventional 6T SRAM cell and can be reduced by increasing motion of electron in the memristor. The change of the memristor state is shown by applying piecewise linear input voltage.展开更多
Pd-Al2O3-Si capacitors with Ru nanocrystals are fabricated and electrically characterized for nonvolatile memory application. While keeping the entire insulator Al2O3 thickness fixed, the memory window has a strong de...Pd-Al2O3-Si capacitors with Ru nanocrystals are fabricated and electrically characterized for nonvolatile memory application. While keeping the entire insulator Al2O3 thickness fixed, the memory window has a strong dependence on the tunneling layer thickness under low operating voltages, whereas it has weak dependence under high operating voltages. As for the optimal configuration comprised of 6-nm tunneling layer and 22-nm blocking layer, the resulting memory window increases from 1.5 V to 5.3 V with bias pulse increasing from 10-5 s to 10-2 s under ±7 V. A ten-year memory window as large as 5.2 V is extrapolated at room temperature after ±8 V/1 ms programming/erasing pulses.展开更多
The exploration of novel photo/thermal-responsive nonvolatile memorizers will be beneficial for energysaving memories.Herein,new<110>-oriented perovskites using single template melamine,i.e.,[(MLAI-H_(2))(PbX_(4...The exploration of novel photo/thermal-responsive nonvolatile memorizers will be beneficial for energysaving memories.Herein,new<110>-oriented perovskites using single template melamine,i.e.,[(MLAI-H_(2))(PbX_(4))]_n(X=Br (α-1),Cl (α-2),MLAI=melamine) have been prepared and their structures upon irradiation of visible light have been investigated.They have been fabricated as nonvolatile memory devices with structures of ITO/[(MLAI-H_(2))(PbX_(4))]_n/PMMA/Ag (device-1:X=Br,device-2:X=Cl),which can exhibit unique visible light-triggered binary nonvolatile memory performances.Interestingly,the silent or working status can be monitored by visible chromisms.Furthermore,the light-triggered binary resistive switching mechanisms of these ITO/[(MLAI-H_(2))(PbX_(4))]_n/PMMA/Ag memory devices have been clarified in terms of EPR,fluorescence,and single-crystal structural analysis.The presence of light-activated traps in<110>-oriented[(MLAI-H_(2))(PbX_(4))]_n perovskites are dominated in the appearance of light-triggered resistive switching behaviors,based on which the inverted internal electrical fields can be established.According to the structural analysis,the more distorted PbX_6octahedra,higher corrugated<110>-oriented perovskite sheets,and more condensed organic-inorganic packing in Br-containing perovskite are beneficial for the stabilization of light-activated traps,which lead to the better resistive switching behavior of device-1.This work can pave a new avenue for the establishment of novel energy-saving nonvolatile memorizers used in aerospace or military industries.展开更多
A method of fabricating Cu nanocrystals embedded in SiO2 dielectric film for nonvolatile memory applications by magnetron sputtering is introduced in this paper. The average size and distribution density of Cu nanocry...A method of fabricating Cu nanocrystals embedded in SiO2 dielectric film for nonvolatile memory applications by magnetron sputtering is introduced in this paper. The average size and distribution density of Cu nanocrystal grains are controlled by adjusting experimental parameters. The relationship between nanocrystal floating gate micro-structure and its charge storage capability is also discussed theoretically.展开更多
Amorphous In–Ga–Zn–O(a-IGZO)thin-film transistor(TFT)memories with novel p-SnO/n-SnO_(2) heterojunction charge trapping stacks(CTSs)are investigated comparatively under a maximum fabrication temperature of 280℃.Co...Amorphous In–Ga–Zn–O(a-IGZO)thin-film transistor(TFT)memories with novel p-SnO/n-SnO_(2) heterojunction charge trapping stacks(CTSs)are investigated comparatively under a maximum fabrication temperature of 280℃.Compared to a single p-SnO or n-SnO_(2) charge trapping layer(CTL),the heterojunction CTSs can achieve electrically programmable and erasable characteristics as well as good data retention.Of the two CTSs,the tunneling layer/p-SnO/nSnO_(2)/blocking layer architecture demonstrates much higher program efficiency,more robust data retention,and comparably superior erase characteristics.The resulting memory window is as large as 6.66 V after programming at 13 V/1 ms and erasing at-8 V/1 ms,and the ten-year memory window is extrapolated to be 4.41 V.This is attributed to shallow traps in p-SnO and deep traps in n-SnO_(2),and the formation of a built-in electric field in the heterojunction.展开更多
The N2-plasma treatment on a HfO2 blocking layer of Au nanocrystal nonvolatile memory without any post annealing is investigated. The electrical characteristics of the MOS capacitor with structure of Al–Ta N/HfO2/Si ...The N2-plasma treatment on a HfO2 blocking layer of Au nanocrystal nonvolatile memory without any post annealing is investigated. The electrical characteristics of the MOS capacitor with structure of Al–Ta N/HfO2/Si O2/p-Si are also characterized. After N2-plasma treatment, the nitrogen atoms are incorporated into HfO2 film and may passivate the oxygen vacancy states. The surface roughness of HfO2 film can also be reduced. Those improvements of HfO2 film lead to a smaller hysteresis and lower leakage current density of the MOS capacitor. The N2-plasma is introduced into Au nanocrystal（NC） nonvolatile memory to treat the HfO2 blocking layer. For the N2-plasma treated device, it shows a better retention characteristic and is twice as large in the memory window than that for the no N2-plasma treated device. It can be concluded that the N2-plasma treatment method can be applied to future nonvolatile memory applications.展开更多
A novel high-κ~ A1203/HfO2/AI203 nanolaminate charge trapping memory capacitor structure based on SiGe substrates with low interface densities is successfully fabricated and investigated. The memory capacitor exhibit...A novel high-κ~ A1203/HfO2/AI203 nanolaminate charge trapping memory capacitor structure based on SiGe substrates with low interface densities is successfully fabricated and investigated. The memory capacitor exhibits excellent program-erasable characteristics. A large memory window of ~4 V, a small leakage current density of ~2 ×10-6 Acre-2 at a gate voltage of 7V, a high charge trapping density of 1.42 × 1013 cm-2 at a working vo]tage of 4-10 V and good retention characteristics are observed. Furthermore, the programming （△ VFB = 2.8 V at 10 V for 10μs） and erasing speeds （△VFB =-1.7 V at -10 V for 10μs） of the fabricated capacitor based on SiGe substrates are significantly improved as compared with counterparts reported earlier. It is concluded that the high-κ Al2O3/HfO2/Al2O3 nanolaminate charge trapping capacitor structure based on SiGe substrates is a promising candidate for future nano-scaled nonvolatile flash memory applications.展开更多
Based on the charge storage mode,it is important to investigate the scaling dependence of memory performance in silicon nanocrystal（Si-NC） nonvolatile memory（NVM） devices for its scaling down limit.In this work,we...Based on the charge storage mode,it is important to investigate the scaling dependence of memory performance in silicon nanocrystal（Si-NC） nonvolatile memory（NVM） devices for its scaling down limit.In this work,we made eight kinds of test key cells with different gate widths and lengths by 0.13-μm node complementary metal oxide semiconductor（CMOS） technology.It is found that the memory windows of eight kinds of test key cells are almost the same of about1.64 V @ ±7 V/1 ms,which are independent of the gate area,but mainly determined by the average size（12 nm） and areal density（1.8×10^（11）/cm^2） of Si-NCs.The program/erase（P/E） speed characteristics are almost independent of gate widths and lengths.However,the erase speed is faster than the program speed of test key cells,which is due to the different charging behaviors between electrons and holes during the operation processes.Furthermore,the data retention characteristic is also independent of the gate area.Our findings are useful for further scaling down of Si-NC NVM devices to improve the performance and on-chip integration.展开更多
Graphene’s unique photothermoelectric(PTE)effect,combined with its compatibility for on-chip fabrication,promises its development in chip-integrated photodetectors with ultralow dark-current and ultrafast speed.Previ...Graphene’s unique photothermoelectric(PTE)effect,combined with its compatibility for on-chip fabrication,promises its development in chip-integrated photodetectors with ultralow dark-current and ultrafast speed.Previous designs of on-chip graphene photodetectors required external electrical biases or gate voltages to separate photocarriers,leading to increased power consumption and complex circuitry.Here,we demonstrate a nonvolatile graphene p–i–n homojunction constructed on a silicon photonic crystal waveguide,which facilitates PTE-based photodetection without the need for electrical bias or gate voltages.By designing an air-slotted photonic crystal waveguide as two individual silicon back gates and employing ferroelectric dielectrics with remnant polarization fields,the nonvolatile p–i–n homojunction with a clear gradient of Seebeck coefficient is electrically configured.Hot carriers in the graphene channel generated from the absorption of waveguide evanescent field are separated by the nonvolatile p–i–n homojunction effectively to yield considerable photocurrents.With zero-bias and zero-gate voltage,the nonvolatile graphene p–i–n homojunction photodetector integrated on the optical waveguide exhibits high and flat responsivity of 193 mAW^(−1)over the broadband wavelength range of 1560–1630 nm and an ultrafast dynamics bandwidth of 17 GHz measured in the limits of our instruments.With the high-performance on-chip photodetection,the nonvolatile graphene homojunction directly constructed on silicon photonic circuits promises the extended on-chip functions of the optoelectronic synapse,in-memory sensing and computing,and neuromorphic computing.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12074213,11574108,and 12104253)the National Key R&D Program of China(Grant No.2022YFA1403103)+2 种基金the Major Basic Program of the Natural Science Foundation of Shandong Province(Grant No.ZR2021ZD01)the Natural Science Foundation of Shandong Provincial(Grant No.ZR2023MA082)the Project of Introduction and Cultivation for Young Innovative Talents in Colleges and Universities of Shandong Province。
文摘Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a promising alternative to achieve low power consumption and nonvolatile electric control of magnetic properties.In this paper,a two-dimensional multiferroic van der Waals heterostructure OsCl_(2)/Sc_(2)CO_(2),which is composed of ferromagnetic monolayer OsCl_(2)and ferroelectric monolayer Sc_(2)CO_(2),is studied by first-principles density functional theory.The results show that by reversing the direction of the electric polarization of Sc_(2)CO_(2),OsCl_(2)can be transformed from a semiconductor to a half-metal,demonstrating a nonvolatile electrical manipulation of the heterostructure through ferroelectric polarization.The underlying physical mechanism is explained by band alignments and charge density differences.Furthermore,based on the heterostructure,we construct a multiferroic tunnel junction with a tunnel electroresistance ratio of 3.38×10^(14)%and a tunnel magnetoresistance ratio of 5.04×10^(6)%,allowing control of conduction states via instantaneous electric or magnetic fields.The findings provide a feasible strategy for designing advanced nanodevices based on the giant tunnel electroresistance and tunnel magnetoresistance effects.
基金supported by the National Natural Science Foundation of China(Grant Nos.62174016,12474047,12204202,and 11974355)the Basic Research Program of Jiangsu(Grant No.BK20220679)+1 种基金the Fund for Shanxi“1331Project”the Research Project Supported by Shanxi Scholarship Council of China.
文摘The presence of a van Hove singularity(vHS)at the Fermi level can trigger magnetic instability by mediating a spontaneous transition from paramagnetic to magnetically ordered states.While electrostatic doping(typically achieved via ionic gating)to shift the vHS to the Fermi level provides a general mechanism for engineering such magnetism,its volatile nature often leads to the collapse of induced states upon gate field removal.Here,a novel scheme is presented for non-volatile magnetic control by utilizing ferroelectric heterostructures to achieve reversible magnetism switching.Using two-dimensional VSiN_(3),a nonmagnetic material with Mexican-hat electronic band dispersions hosting vHSs,as a prototype,it is preliminarily demonstrated that both electron and hole doping can robustly induce magnetism.Further,by interfacing VSiN_(3)with ferroelectric Sc_(2)CO_(2),reversible switching of its magnetic state via polarization-driven heterointerfacial charge transfer is achieved.This mechanism enables a dynamic transition between insulating and half-metallic phases in VSiN_(3),establishing a pathway to design multiferroic tunnel junctions with giant tunneling electroresistance or magnetoresistance.This work bridges non-volatile ferroelectric control with vHS-enhanced magnetism,opening opportunities for energy-efficient and high-performance spintronic devices and non-volatile memory devices.
基金supported by the National Key R&D Program of China(Grant No.2024YFA1408103)National Natural Science Foundation of China(Grants No.11974098,12474158,12234017 and 12488101)+3 种基金Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302800)Natural Science Foundation of Hebei Province(Grant No.A202305017)Anhui Initiative in Quantum Information Technologies(Grant No.AHY170000)Fundamental Research Funds for the Central Universities(Grant No.WK2340000082)。
文摘Interlayer antiferromagnetic coupling,small magnetic anisotropy,and low air stability of the intrinsic magnetic topological insulator MnBi_(2)Te_(4)have been critical bottlenecks to the future application of the quantum anomalous Hall efect(QAHE)at zero magnetic feld.In this study,we propose a scheme to utilize capped sliding van der Waals materials to efectively modulate the magnetic and topological properties of MnBi_(2)Te_(4).Our results demonstrate that the h-BN/MnBi_(2)Te_(4)/h-BN heterostructure,constructed by sliding ferroelectric h-BN bilayer and MnBi_(2)Te_(4),not only realizes a transition from interlayer antiferromagnetic to ferromagnetic coupling but also signifcantly enhances the out-of-plane magnetism and air stability of MnBi_(2)Te_(4).Moreover,the above magnetic properties can be further improved by tuning the interlayer distance between h-BN and MnBi_(2)Te_(4).Additionally,the obtained band structures and topological properties clearly support that the h-BN/MnBi_(2)Te_(4)/hBN heterostructure can harbor the QAHE with a Chern number of C=1.This work provides a new and nonvolatile modulation approach to achieve high-temperature and high-precision QAHE at zero magnetic feld.
基金supported by the National Key Research&Development Projects of China(Grant No.2022YFA1204100)National Natural Science Foundation of China(Grant No.62488201)+1 种基金CAS Project for Young Scientists in Basic Research(YSBR-003)the Innovation Program of Quantum Science and Technology(2021ZD0302700)。
文摘As a typical in-memory computing hardware design, nonvolatile ternary content-addressable memories(TCAMs) enable the logic operation and data storage for high throughout in parallel big data processing. However,TCAM cells based on conventional silicon-based devices suffer from structural complexity and large footprintlimitations. Here, we demonstrate an ultrafast nonvolatile TCAM cell based on the MoTe2/hBN/multilayergraphene (MLG) van der Waals heterostructure using a top-gated partial floating-gate field-effect transistor(PFGFET) architecture. Based on its ambipolar transport properties, the carrier type in the source/drain andcentral channel regions of the MoTe2 channel can be efficiently tuned by the control gate and top gate, respectively,enabling the reconfigurable operation of the device in either memory or FET mode. When working inthe memory mode, it achieves an ultrafast 60 ns programming/erase speed with a current on-off ratio of ∼105,excellent retention capability, and robust endurance. When serving as a reconfigurable transistor, unipolar p-typeand n-type FETs are obtained by adopting ultrafast 60 ns control-gate voltage pulses with different polarities.The monolithic integration of memory and logic within a single device enables the content-addressable memory(CAM) functionality. Finally, by integrating two PFGFETs in parallel, a TCAM cell with a high current ratioof ∼10^(5) between the match and mismatch states is achieved without requiring additional peripheral circuitry.These results provide a promising route for the design of high-performance TCAM devices for future in-memorycomputing applications.
基金Project supported by the National Natural Science Foundation of China （Grant No. 51202045）, the Postdoctoral Science Foundation of Heilongjiang Province, China, and the Fundamental Research Funds for the Central Universities of Ministry of Education of China （Grant No. HIT. NSRIF. 2013004）.
文摘We have grown triply doped Mg:Fe:Mn:LiTaO3 crystals with near stoichiometry using the top seeded solution growth technique. The defect structure was investigated by infrared absorption spectra and Curie temperature. Using a blue laser as the source, excellent photorefractive properties were obtained. Nonvolatile holographic storage properties were investigated using the dual wavelength technique. We got a very high fixed diffraction efficiency and nonvolatile holographic storage sensitivity. The blue light has more than enough energy to excite holes of deep(Mn) and shallow(Fe) trap centers with the same phase, which enhance dramatically the blue photorefractive properties and the nonvolatile holographic storage. Mg2+ ion is no longer damage resistant at blue laser, but enhances photorefractive characteristics.
基金Project supported by the National Advanced Materials Committee of China (Grant No. 2007AA03Z459)Shanxi Provincial Technology Project for Higher Education,China (Grant No. 20091105)
文摘It has been suggested to use LiNbO3：Fe,Mn crystal for solving the problem of information volatility during the read-out process with all-optical facilities,but the minute order response time is far from the requirements for the real-time information processing.We present the nonvolatile holographic storage properties of LiNbO3：Hf,Fe,Mn.The response time is shortened to 5.0 s,and the sensitivity S is enhanced to 0.22 cm/J in this triply doped crystal.The experimental results show that the HfO2 doping threshold is 5.0 mol.%.Thus it seems that we have found a useful tetravalent dopant for LiNbO3：Fe,Mn that can obviously improve the nonvolatile holographic recording sensitivity.
基金supported by the GIK Institute of Engineering Science and Technology,Pakistan and Physical Technical Institute of Academy of Sciences of Tajikistan
文摘A novel surface-type nonvolatile electric memory elements based on organic semiconductors CuPc and H2Pc are fabricated by vacuum deposition of the CuPc and H2Pc films on preliminary deposited metallic （Ag and Cu） electrodes. The gap between Ag and Cu electrodes is 3040μm. For the current-voltage （I-V） characteristics the memory effect, switching effect, and negative differential resistance regions are observed. The switching mechanism is attributed to the electric-field-induced charge transfer. As a result the device switches from a low to a high-conductivity state and then back to a low conductivity state if the opposite polarity voltage is applied. The ratio of resistance at the high resistance state to that at the low resistance state is equal to 120-150. Under the switching condition, the electric current increases -- 80-100 times. A comparison between the forward and reverse I-V characteristics shows the presence of rectifying behavior.
基金Supported by the Joint Funds of the National Natural Science Foundation of China and the Chinese Academy of Sciences’Large-Scale Scientific Facility under Grant No U1532149the National Basic Research Program of China under Grant No2014CB931704
文摘Polycrystalline LaCrO3（LCO） thin films are deposited on Pt/Ti/SiO2/Si substrates by pulsed laser deposition and used as the switching material to construct resistive random access memory devices. The unipolar resistive switching（RS） behavior in the Au/LCO/Pt devices exhibits a high resistance ratio of ~104 between the high resistance state（HRS） and low resistance state（LRS） and exhibits excellent endurance/retention characteristics.The conduction mechanism of the HRS in the high voltage range is dominated by the Schottky emission, while the Ohmic conduction dictates the LRS and the low voltage range of HRS. The RS behavior in the Au/LCO/Pt devices can be understood by the formation and rupture of conducting filaments consisting of oxygen vacancies,which is validated by the temperature dependence of resistance and x-ray photoelectron spectroscopy results.Further analysis shows that the reset current IR and reset power PR in the reset processes exhibit a scaling law with the resistance in LRS（R0）, which indicates that the Joule heating effect plays an essential role in the RS behavior of the Au/LCO/Pt devices.
基金Project supported by the Fundamental Research Funds for the Central Universities of China (Grant No. DL12AB03)the National Natural Science Founda-tion of China (Grant No. 60777006)
文摘Mg：Ru：Fe：LiN-bO3 crystals with various concentrations of MgO （in mole） and fixed content of RuO2 and Fe203 （in mass） are grown with the Czochralski method from the congruent melt. Their infrared transmission spectra are mea- sured and discussed to investigate the defect structure. With the increase of Mg2＋ concentration the blue nonvolatile holographic storage capability is enhanced. The nonvolatile holographic storage properties of dual-wavelength recording of Mg（7 mol%）：Ru：Fe：LiNbO3 nonvolatile diffraction efficiency, response time, and nonvolatile sensitivity reach 59.8%, 70 s, and 1.04 cm/J, respectively. Comparing Mg（7 mol%）：Ru：Fe：LiNbO3 with Ru：Fe：LiNbO3 crystal, the response time is shortened apparently. The nonvolatile diffraction efficiency and sensitivity are raised largely. The mechanism in blue photorefractive nonvolatile holographic storage is discussed.
文摘Demands for low-energy microcontrollers have been increasing in recent years. Since most microcontrollers achieve user programmability by integrating nonvolatile (NV) memories such as flash memories for storing their programs, the large power consumption required in accessing an NV memory has become a major problem. This problem becomes critical when the power supply voltage of NV microcontrollers is decreased. We can solve this problem by introducing an instruction cache, thus reducing the access frequency of the NV memory. Unlike general-purpose microprocessors, microcontrollers used for real-time applications in embedded systems must accurately calculate program execution time prior to its execution. Therefore, we introduce a “transparent” instruction cache, which does not change the existing NV microcontroller’s cycle-level execution time, for reducing power and energy consumption, but not for improving the processing speed. We have conducted detailed microar chitecture design based on the architecture of a major industrial microcontroller, and we evaluated power and energy consumption for several benchmark programs. Our evaluation shows that the proposed instruction cache can successfully reduce energy consumption in a fairly wide range of practical NV microcontroller configurations.
文摘IEEE J.Solid-State Circuits,2019,doi:10.1109/JSSC.2018.2884349Nonvolatile processor(NVP)is promising for energy-harvesting-powered internet-of-things(IoT)devices,owing to its unique capability to sustain computation progress over power outages.Recently.
文摘Memristor is a newly found fourth circuit element for the next generation emerging nonvolatile memory technology. In this paper, design of new type of nonvolatile static random access memory cell is proposed by using a combination of memristor and complemented metal oxide semiconductor. Biolek memristor model and CMOS 180 nm technology are used to form a single cell. By introducing distinct binary logic to avoid safety margin is left for each binary logic output and enables better read/write data integrity. The total power consumption reduces from 0.407 mw (milli-watt) to 0.127 mw which is less than existing memristor based memory cell of the same CMOS technology. Read and write time is also significantly reduced. However, write time is higher than conventional 6T SRAM cell and can be reduced by increasing motion of electron in the memristor. The change of the memristor state is shown by applying piecewise linear input voltage.
基金Project supported by the National Key Technology Research and Development Program of China(Grant No.2009ZX02302-002)the National Natural Science Foundation of China(Grant No.61274088)the Program for New Century Excellent Talents in University of Ministry of Education of China(Grant No.NCET-08-0127)
文摘Pd-Al2O3-Si capacitors with Ru nanocrystals are fabricated and electrically characterized for nonvolatile memory application. While keeping the entire insulator Al2O3 thickness fixed, the memory window has a strong dependence on the tunneling layer thickness under low operating voltages, whereas it has weak dependence under high operating voltages. As for the optimal configuration comprised of 6-nm tunneling layer and 22-nm blocking layer, the resulting memory window increases from 1.5 V to 5.3 V with bias pulse increasing from 10-5 s to 10-2 s under ±7 V. A ten-year memory window as large as 5.2 V is extrapolated at room temperature after ±8 V/1 ms programming/erasing pulses.
基金financially supported by the Natural Science Foundation of Fujian Province(Nos.2021J02007,2021J01553)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZR148)。
文摘The exploration of novel photo/thermal-responsive nonvolatile memorizers will be beneficial for energysaving memories.Herein,new<110>-oriented perovskites using single template melamine,i.e.,[(MLAI-H_(2))(PbX_(4))]_n(X=Br (α-1),Cl (α-2),MLAI=melamine) have been prepared and their structures upon irradiation of visible light have been investigated.They have been fabricated as nonvolatile memory devices with structures of ITO/[(MLAI-H_(2))(PbX_(4))]_n/PMMA/Ag (device-1:X=Br,device-2:X=Cl),which can exhibit unique visible light-triggered binary nonvolatile memory performances.Interestingly,the silent or working status can be monitored by visible chromisms.Furthermore,the light-triggered binary resistive switching mechanisms of these ITO/[(MLAI-H_(2))(PbX_(4))]_n/PMMA/Ag memory devices have been clarified in terms of EPR,fluorescence,and single-crystal structural analysis.The presence of light-activated traps in<110>-oriented[(MLAI-H_(2))(PbX_(4))]_n perovskites are dominated in the appearance of light-triggered resistive switching behaviors,based on which the inverted internal electrical fields can be established.According to the structural analysis,the more distorted PbX_6octahedra,higher corrugated<110>-oriented perovskite sheets,and more condensed organic-inorganic packing in Br-containing perovskite are beneficial for the stabilization of light-activated traps,which lead to the better resistive switching behavior of device-1.This work can pave a new avenue for the establishment of novel energy-saving nonvolatile memorizers used in aerospace or military industries.
文摘A method of fabricating Cu nanocrystals embedded in SiO2 dielectric film for nonvolatile memory applications by magnetron sputtering is introduced in this paper. The average size and distribution density of Cu nanocrystal grains are controlled by adjusting experimental parameters. The relationship between nanocrystal floating gate micro-structure and its charge storage capability is also discussed theoretically.
基金Project supported by the National Natural Science Foundation of China (Grant No.61874029)。
文摘Amorphous In–Ga–Zn–O(a-IGZO)thin-film transistor(TFT)memories with novel p-SnO/n-SnO_(2) heterojunction charge trapping stacks(CTSs)are investigated comparatively under a maximum fabrication temperature of 280℃.Compared to a single p-SnO or n-SnO_(2) charge trapping layer(CTL),the heterojunction CTSs can achieve electrically programmable and erasable characteristics as well as good data retention.Of the two CTSs,the tunneling layer/p-SnO/nSnO_(2)/blocking layer architecture demonstrates much higher program efficiency,more robust data retention,and comparably superior erase characteristics.The resulting memory window is as large as 6.66 V after programming at 13 V/1 ms and erasing at-8 V/1 ms,and the ten-year memory window is extrapolated to be 4.41 V.This is attributed to shallow traps in p-SnO and deep traps in n-SnO_(2),and the formation of a built-in electric field in the heterojunction.
基金supported by the High Level Talent Project of Xiamen University of Technology,China(Grant Nos.YKJ16012R and YKJ16016R)the National Natural Science Foundation of China(Grant No.51702271)
文摘The N2-plasma treatment on a HfO2 blocking layer of Au nanocrystal nonvolatile memory without any post annealing is investigated. The electrical characteristics of the MOS capacitor with structure of Al–Ta N/HfO2/Si O2/p-Si are also characterized. After N2-plasma treatment, the nitrogen atoms are incorporated into HfO2 film and may passivate the oxygen vacancy states. The surface roughness of HfO2 film can also be reduced. Those improvements of HfO2 film lead to a smaller hysteresis and lower leakage current density of the MOS capacitor. The N2-plasma is introduced into Au nanocrystal（NC） nonvolatile memory to treat the HfO2 blocking layer. For the N2-plasma treated device, it shows a better retention characteristic and is twice as large in the memory window than that for the no N2-plasma treated device. It can be concluded that the N2-plasma treatment method can be applied to future nonvolatile memory applications.
基金Supported by the National Science and Technology Major Project of China under Grant No 2013ZX02303007the National Key Research and Development Program of China under Grant No 2016YFA0301701the Youth Innovation Promotion Association of the Chinese Academy of Sciences under Grant No 2016112
文摘A novel high-κ~ A1203/HfO2/AI203 nanolaminate charge trapping memory capacitor structure based on SiGe substrates with low interface densities is successfully fabricated and investigated. The memory capacitor exhibits excellent program-erasable characteristics. A large memory window of ~4 V, a small leakage current density of ~2 ×10-6 Acre-2 at a gate voltage of 7V, a high charge trapping density of 1.42 × 1013 cm-2 at a working vo]tage of 4-10 V and good retention characteristics are observed. Furthermore, the programming （△ VFB = 2.8 V at 10 V for 10μs） and erasing speeds （△VFB =-1.7 V at -10 V for 10μs） of the fabricated capacitor based on SiGe substrates are significantly improved as compared with counterparts reported earlier. It is concluded that the high-κ Al2O3/HfO2/Al2O3 nanolaminate charge trapping capacitor structure based on SiGe substrates is a promising candidate for future nano-scaled nonvolatile flash memory applications.
基金Project supported by the State Key Development Program for Basic Research of China(Grant No.2010CB934402)the National Natural Science Foundation of China(Grant Nos.11374153,61571221,and 61071008)
文摘Based on the charge storage mode,it is important to investigate the scaling dependence of memory performance in silicon nanocrystal（Si-NC） nonvolatile memory（NVM） devices for its scaling down limit.In this work,we made eight kinds of test key cells with different gate widths and lengths by 0.13-μm node complementary metal oxide semiconductor（CMOS） technology.It is found that the memory windows of eight kinds of test key cells are almost the same of about1.64 V @ ±7 V/1 ms,which are independent of the gate area,but mainly determined by the average size（12 nm） and areal density（1.8×10^（11）/cm^2） of Si-NCs.The program/erase（P/E） speed characteristics are almost independent of gate widths and lengths.However,the erase speed is faster than the program speed of test key cells,which is due to the different charging behaviors between electrons and holes during the operation processes.Furthermore,the data retention characteristic is also independent of the gate area.Our findings are useful for further scaling down of Si-NC NVM devices to improve the performance and on-chip integration.
基金supported by the Key Research and Development Program(2022YFA1404800)the National Natural Science Foundation of China(12374359 and 62375225)+1 种基金the Shaanxi Fundamental Science Research Project for Mathematics and Physics(22JSY004)the Xi’an Science and Technology Plan Project(2023JH-ZCGJ-0023).
文摘Graphene’s unique photothermoelectric(PTE)effect,combined with its compatibility for on-chip fabrication,promises its development in chip-integrated photodetectors with ultralow dark-current and ultrafast speed.Previous designs of on-chip graphene photodetectors required external electrical biases or gate voltages to separate photocarriers,leading to increased power consumption and complex circuitry.Here,we demonstrate a nonvolatile graphene p–i–n homojunction constructed on a silicon photonic crystal waveguide,which facilitates PTE-based photodetection without the need for electrical bias or gate voltages.By designing an air-slotted photonic crystal waveguide as two individual silicon back gates and employing ferroelectric dielectrics with remnant polarization fields,the nonvolatile p–i–n homojunction with a clear gradient of Seebeck coefficient is electrically configured.Hot carriers in the graphene channel generated from the absorption of waveguide evanescent field are separated by the nonvolatile p–i–n homojunction effectively to yield considerable photocurrents.With zero-bias and zero-gate voltage,the nonvolatile graphene p–i–n homojunction photodetector integrated on the optical waveguide exhibits high and flat responsivity of 193 mAW^(−1)over the broadband wavelength range of 1560–1630 nm and an ultrafast dynamics bandwidth of 17 GHz measured in the limits of our instruments.With the high-performance on-chip photodetection,the nonvolatile graphene homojunction directly constructed on silicon photonic circuits promises the extended on-chip functions of the optoelectronic synapse,in-memory sensing and computing,and neuromorphic computing.
