In HfO_(2),the stabilization of orthorhombic phase is crucial for hafnia-based ferroelectric devices.Here,we propose a charge-balance synergistic strategy to modulate phase transition and optimize ferroelectric proper...In HfO_(2),the stabilization of orthorhombic phase is crucial for hafnia-based ferroelectric devices.Here,we propose a charge-balance synergistic strategy to modulate phase transition and optimize ferroelectric properties in acceptor-doped HfO_(2)thin-film heterostructures.Sm-doped HfO_(2)/SrRuO_(3)heterostructures are adopted as the platform,in which the acceptor SmʹHf introduces extra holes into the HfO_(2)controlled by doping concentration,while the SrRuO_(3)electrode injects electrons depended on termination-controlled surface work function.Transition from monoclinic to orthorhombic and then to tetragonal phase is observed with increasing Sm concentration.The Sm-doping region for improved ferroelectricity is found to be depended on SrRuO_(3)termination.These behaviors are ascribed to the charge-balance effect that combines the acceptor doping and the interface injection in the heterostructures.The holes in HfO_(2)lattices are thus modulated to dominantly distribute on specific oxygen sublattices,lowering the relative energy between monoclinic and orthorhombic phases.We also extend the study into other acceptor-doped HfO_(2),such as La^(3+)and Eu^(3+),and observe almost identical phase transition and ferroelectric behaviors.Our findings provide more physical insights into the stabilization of orthorhombic phase and open a new gateway for designing high-performance ferroelectric HfO_(2)devices by harnessing both the electrode structures and the HfO_(2)-based layers in heterostructure systems.展开更多
Scandium-doped aluminum nitride(AlScN)with an asymmetric hexagonal wurtzite structure exhibits enhanced second-order nonlinear and piezoelectric properties compared to aluminum nitride(AlN),while maintaining a relativ...Scandium-doped aluminum nitride(AlScN)with an asymmetric hexagonal wurtzite structure exhibits enhanced second-order nonlinear and piezoelectric properties compared to aluminum nitride(AlN),while maintaining a relatively large bandgap.It provides a promising platform for photonic circuits and facilitates the seamless integration of passive and active functional devices.Here,we present the design,fabrication,and characterization of Al_(0.904)Sc_(0.096)N electro-optic(EO)micro-ring modulators,introducing active functionalities to the chip-scale AlScN platform.These waveguide-integrated EO modulators utilize sputtered Al_(0.904)Sc_(0.096)N thin films as the light-guiding medium,with the entire fabrication process being compatible with complementary metaloxide-semiconductor(CMOS)technology.We extract the in-device effective EO coefficient of 2.86 pm/V at12 GHz.The devices show a minimum half-wave voltage-length product of 3.12 V·cm at a modulation frequency of 14 GHz,and achieve a 3-dB modulation bandwidth of approximately 22 GHz.Our work provides a promising modulation scheme for cost-effective silicon-integrated photonics systems.展开更多
Optical control of magnons in two-dimensional(2D)materials promises new functionalities for spintronics and magnonics in atomically thin devices.Here,we report control of magnon dynamics,using laser polarization,in a ...Optical control of magnons in two-dimensional(2D)materials promises new functionalities for spintronics and magnonics in atomically thin devices.Here,we report control of magnon dynamics,using laser polarization,in a ferromagnetic van der Waals(vdW)material,Fe3.6Co1.4GeTe2.The magnon amplitude,frequency,and lifetime are controlled and monitored by time-resolved pump-probe spectroscopy.We show substantial(over 25%)and continuous modulation of magnon dynamics as a function of incident laser polarization.Our results suggest that the modification of the effective demagnetization field and magnetic anisotropy by the pump laser pulses with different polarizations is due to anisotropic optical absorption.This implies that pump laser pulses modify the local spin environment,which enables the launch of magnons with tunable dynamics.Our first-principles calculations confirm the anisotropic optical absorption of different crystal orientations.Our findings suggest a new route for the development of opto-spintronic or opto-magnonic devices.展开更多
基金sponsored by Natural Science Foundation of China(Grants No.52372113 and 12474061)Natural Science Basic Research Program of Shaanxi(Program No.2024JC-YBMS-009)+1 种基金Z.W.acknowledges support from the Taishan Scholar Program of Shandong Province(Grants No.tstp20240511)T.C.thanks the support from the Youth Project of“Shanxi High-level Talents Introduction Plan and Shaanxi Qinchuangyuan High-Level Innovative and Entrepreneurial Talent Introduction Program(QCYRCXM-2023-077)。
文摘In HfO_(2),the stabilization of orthorhombic phase is crucial for hafnia-based ferroelectric devices.Here,we propose a charge-balance synergistic strategy to modulate phase transition and optimize ferroelectric properties in acceptor-doped HfO_(2)thin-film heterostructures.Sm-doped HfO_(2)/SrRuO_(3)heterostructures are adopted as the platform,in which the acceptor SmʹHf introduces extra holes into the HfO_(2)controlled by doping concentration,while the SrRuO_(3)electrode injects electrons depended on termination-controlled surface work function.Transition from monoclinic to orthorhombic and then to tetragonal phase is observed with increasing Sm concentration.The Sm-doping region for improved ferroelectricity is found to be depended on SrRuO_(3)termination.These behaviors are ascribed to the charge-balance effect that combines the acceptor doping and the interface injection in the heterostructures.The holes in HfO_(2)lattices are thus modulated to dominantly distribute on specific oxygen sublattices,lowering the relative energy between monoclinic and orthorhombic phases.We also extend the study into other acceptor-doped HfO_(2),such as La^(3+)and Eu^(3+),and observe almost identical phase transition and ferroelectric behaviors.Our findings provide more physical insights into the stabilization of orthorhombic phase and open a new gateway for designing high-performance ferroelectric HfO_(2)devices by harnessing both the electrode structures and the HfO_(2)-based layers in heterostructure systems.
基金National Natural Science Foundation of China(U23A20356,62205193,62204149)Shanghai Collaborative Innovation Center of Intelligent Sensing Chip TechnologyNatural Science Foundation of Shanghai Municipality(23ZR1442400)。
文摘Scandium-doped aluminum nitride(AlScN)with an asymmetric hexagonal wurtzite structure exhibits enhanced second-order nonlinear and piezoelectric properties compared to aluminum nitride(AlN),while maintaining a relatively large bandgap.It provides a promising platform for photonic circuits and facilitates the seamless integration of passive and active functional devices.Here,we present the design,fabrication,and characterization of Al_(0.904)Sc_(0.096)N electro-optic(EO)micro-ring modulators,introducing active functionalities to the chip-scale AlScN platform.These waveguide-integrated EO modulators utilize sputtered Al_(0.904)Sc_(0.096)N thin films as the light-guiding medium,with the entire fabrication process being compatible with complementary metaloxide-semiconductor(CMOS)technology.We extract the in-device effective EO coefficient of 2.86 pm/V at12 GHz.The devices show a minimum half-wave voltage-length product of 3.12 V·cm at a modulation frequency of 14 GHz,and achieve a 3-dB modulation bandwidth of approximately 22 GHz.Our work provides a promising modulation scheme for cost-effective silicon-integrated photonics systems.
基金Research reported in this publication was supported in part by the NSF and SC EPSCoR/IDeA Program under NSF Award#OIA-1655740(GEAR CRP 20-GC02,23-GC01)and NSF Award No.2030128,2110033supported in part by the US Department of Energy,Office of Science,Office of Workforce Development for Teachers and Scientists(WDTS)under the Visiting Faculty Program(VFP)+1 种基金support from the Air Force Office of Scientific Research under Award No.FA9550-22-1-0349 and National Science Foundation under Award No.DMR-2326944 and No.DMR-2340773the support from the program of Educational Department of Liaoning Province(grant no.LQGD2020008).
文摘Optical control of magnons in two-dimensional(2D)materials promises new functionalities for spintronics and magnonics in atomically thin devices.Here,we report control of magnon dynamics,using laser polarization,in a ferromagnetic van der Waals(vdW)material,Fe3.6Co1.4GeTe2.The magnon amplitude,frequency,and lifetime are controlled and monitored by time-resolved pump-probe spectroscopy.We show substantial(over 25%)and continuous modulation of magnon dynamics as a function of incident laser polarization.Our results suggest that the modification of the effective demagnetization field and magnetic anisotropy by the pump laser pulses with different polarizations is due to anisotropic optical absorption.This implies that pump laser pulses modify the local spin environment,which enables the launch of magnons with tunable dynamics.Our first-principles calculations confirm the anisotropic optical absorption of different crystal orientations.Our findings suggest a new route for the development of opto-spintronic or opto-magnonic devices.
