The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method na...The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method named plasma-based atom-selective etching(PASE)is proposed to achieve the highly efficient,atomic-scale,and damage-free polishing of β-Ga_(2)O_(3).The plasma is excited through the inductive coupling principle and carbon tetrafluoride is utilized as the main reaction gas to etch β-Ga_(2)O_(3).The core of PASE polishing of β-Ga_(2)O_(3)is the remarkable lateral etching effect,which is ensured by both the intrinsic property of the surface and the extrinsic temperature condition.As revealed by density functional theory-based calculations,the intrinsic difference in the etching energy barrier of atoms at the step edge(2.36 eV)and in the terrace plane(4.37 eV)determines their difference in the etching rate,and their etching rate difference can be greatly enlarged by increasing the extrinsic temperature.The polishing of β-Ga_(2)O_(3)based on the lateral etching effect is further verified in the etching experiments.The Sa roughness of β-Ga_(2)O_(3)(001)substrate is reduced from 14.8 nm to 0.057 nm within 120 s,and the corresponding material removal rate reaches up to 20.96μm·min^(−1).The polished β-Ga_(2)O_(3)displays significantly improved crystalline quality and photoluminescence intensity,and the polishing effect of PASE is independent of the crystal face of β-Ga_(2)O_(3).In addition,the competition between chemical etching and physical reconstruction,which is determined by temperature and greatly affects the surface state of β-Ga_(2)O_(3),is deeply studied for the first time.These findings not only demonstrate the high-efficiency and high-quality polishing of β-Ga_(2)O_(3)via atmospheric plasma etching but also hold significant implications for guiding future plasma-based surface manufacturing of β-Ga_(2)O_(3).展开更多
The signs of the electric field markers in Figs.2 and 4 of the paper[Chin.Phys.B 32104211(2023)]have been corrected.These modifications do not affect the results derived in the paper.
Atomic and close-to-atomic scale manufacturing(ACSM)aims to provide techniques for manufacturing in various fields,such as circuit manufacturing,high energy physics equipment,and medical devices and materials.The real...Atomic and close-to-atomic scale manufacturing(ACSM)aims to provide techniques for manufacturing in various fields,such as circuit manufacturing,high energy physics equipment,and medical devices and materials.The realization of atomic scale material manipulation depending on the theoretical system of classical mechanics faces great challenges.Understanding and using intermolecular and surface forces are the basis for better designing of ACSM.Transformation of atoms based on scanning tunneling microscopy or atomic force microscopy(AFM)is an essential process to regulate intermolecular interactions.Self-assemble process is a thermodynamic process involving complex intermolecular forces.The competition of these interaction determines structure assembly and packing geometry.For typical nanomachining processes including AFM nanomachining and chemical mechanical polishing,the coupling of chemistry and stress(tribochemistry)assists in the removal of surface atoms.Furthermore,based on the principle of triboelectrochemistry,we expect a further reduction of the potential barrier,and a potential application in high-efficiency atoms removal and fabricating functional coating.Future fundamental research is proposed for achieving high-efficiency and high-accuracy manufacturing with the aiding of external field.This review highlights the significant contribution of intermolecular and surface forces to ACSM,and may accelerate its progress in the in-depth investigation of fundamentals.展开更多
The correlation betweent deformation behavior and atomic-scale heterogeneity of bulk metallic glasses(BMGs)is critical to understand the BMGs'deformation mechanism.In this work,three typical[(Fe_(0.5)Co_(0.5))_(0....The correlation betweent deformation behavior and atomic-scale heterogeneity of bulk metallic glasses(BMGs)is critical to understand the BMGs'deformation mechanism.In this work,three typical[(Fe_(0.5)Co_(0.5))_(0.75)B_(0.2)Si_(0.05)]_(96)Nb_4,Fe_(39)Ni_(39)B_(14.2)Si_(2.75)P_(2.75)Nb_(2.3),and Fe_(50)Ni_(30)P_(13)C_(7)BMGs exhibiting different plasticity were selected,and the correlation between deformation behavior and atomic-scale heterogeneity of Fe-based BMGs was studied.It is found that the serrated flow dynamics of Fe-based BMGs transform from chaotic state to self-organized critical state with increasing plasticity.This transformation is attributed to the increasing atomic-scale heterogeneity caused by the increasing free volume and short-to-medium range order,which facilitates a higher frequency of interaction and multiplication of shear bands,thereby results in a brittle to ductile transition in Fe-based BMGs.This work provides new evidence on heterogeneity in plastic Fe-based BMGs from the aspects of atomic-scale structure,and provides new insight into the plastic deformation of Fe-based BMGs.展开更多
The intrinsic origins and formation of atomic-scale structure in multicomponent alloys remain largely unknown owing to limited simulations and inaccessible experiments.Herein,we report the formation of three-dimension...The intrinsic origins and formation of atomic-scale structure in multicomponent alloys remain largely unknown owing to limited simulations and inaccessible experiments.Herein,we report the formation of three-dimensional periodicity from a disordered atomic-scale structure to an imperfect/perfect ordered cluster and finally to long-range translational and rotational symmetry coupled with Nb heterogeneity.Significant atomic-scale structural clustering and atomic arrangements involving solvent or solute atoms simultaneously occurred during isothermal annealing.A close relationship between atomic-scale structural evolution and composition variation has important implications in depicting the chemical and topological packing during the early crystallization stage in metallic glasses.This work can provide a comprehensive understanding of how short-range orders evolve into long-range periodicity and will further shed light on the origins and nature of metallic glasses.展开更多
Nanocrystalline metals have many functional and structural applications due to their excellent mechanical properties compared to their coarse-grained counterparts. The atomic-scale understanding of the deformation mec...Nanocrystalline metals have many functional and structural applications due to their excellent mechanical properties compared to their coarse-grained counterparts. The atomic-scale understanding of the deformation mechanisms of nanocrystalline metals is important for designing new materials, novel structures and applications. The review presents recent developments in the methods and techniques for in situ deformation mechanism investigations on face-centered-cubic nanocrystalline metals. In the first part,we will briefly introduce some important techniques that have been used for investigating the deformation behaviors of nanomaterials. Then, the size effects and the plasticity behaviors in nanocrystalline metals are discussed as a basis for comparison with the plasticity in bulk materials. In the last part, we show the atomic-scale and time-resolved dynamic deformation processes of nanocrystalline metals using our in-lab developed deformation device.展开更多
Atoms in the microscopic world are the basic building blocks of the macroscopic world. In this work, we construct an atomic-scale electromagnetic theory that bridges optics in the microscopic and macroscopic worlds. A...Atoms in the microscopic world are the basic building blocks of the macroscopic world. In this work, we construct an atomic-scale electromagnetic theory that bridges optics in the microscopic and macroscopic worlds. As the building block of the theory, we use the microscopic polarizability to describe the optical response of a single atom, solve the transport of electromagnetic wave through a single atomic layer under arbitrary incident angle and polarization of the light beam, construct the single atomic layer transfer matrix for light transport across the atomic layer. Based on this transfer matrix, we get the analytical form of the dispersion relation, refractive index, and transmission/reflection coefficient of the macroscopic medium. The developed theory can handle single-layer and few-layers of homogeneous and heterogeneous 2D materials, investigate homogeneous 2D materials with various vacancies or insertion atomic-layer defects, study compound 2D materials with a unit cell composed of several elements in both the lateral and parallel directions with respect to the light transport.展开更多
Atomic-level manufacturing,as the "keystone" of future technology,marks the transformative shift from the micro/nano era based on "classical theory" to the atomic era grounded in "quantum theo...Atomic-level manufacturing,as the "keystone" of future technology,marks the transformative shift from the micro/nano era based on "classical theory" to the atomic era grounded in "quantum theory".It enables the precise control of matter arrangement and composition at the atomic scale,thereby achieving large-scale production of atomically precise and structured products.Electrochemical deposition(ECD),a typical "atom addition" fabrication method for electrochemical atomic and close-to-atomic scale manufacturing(EC-ACSM),enables precise control over material properties at the atomic scale,allowing breakthroughs in revolutionary performance of semiconductors,quantum computing,new materials,nanomedicine,etc.This review explores the fundamentals of EC-ACSM,particularly at the electrode/electrolyte interface,and investigates maskless ECD techniques,highlighting their advantages,limitations,and the role of in situ monitoring and advanced simulations in the process optimization.However,atomic electrochemical deposition faces significant challenges in precise control over atom-ion interactions,electrode-electrolyte interfacial dynamics,and surface defects.In the future,overcoming these obstacles is critical to advancing EC-ACSM and unlocking its full potential in scalability for industrial applications.EC-ACSM can drive the highly customized design of materials and offer strong technological support for the development of future science,ushering in a new atomic era of material innovation and device manufacturing.展开更多
High performance dielectric capacitors are ubiquitous components in the modern electronics industry,owing to the highest power density,fastest charge-discharge rates,and long lifetime.However,the wide application of d...High performance dielectric capacitors are ubiquitous components in the modern electronics industry,owing to the highest power density,fastest charge-discharge rates,and long lifetime.However,the wide application of dielectric capacitors is limited owing to the low energy density.Over the past decades,multiscale structures of dielectric ceramics have been extensively explored and many exciting developments have been achieved.Despite the rapid development of energy storage properties,the atomic structure of dielectric materials is rarely investigated.In this paper,we present a brief overview of how scanning transmission electron microscopy(STEM)is used as a tool to elucidate the morphology,local structure heterogeneity,atomic resolution structure phase evolution and the correlation with energy storage properties,which provides a powerful tool for rational design and synergistic optimization.展开更多
The catalysis of Au thin film could be improved by fabrication of array structures in large area.In this work,nanoimprint lithography has been developed tofabricate flexible Au micro-array(MA)electrodes with~100%cover...The catalysis of Au thin film could be improved by fabrication of array structures in large area.In this work,nanoimprint lithography has been developed tofabricate flexible Au micro-array(MA)electrodes with~100%coverage.Advanced electron microscopy characterisations have directly visualised the atomic-scale three-dimensional(3D)nanostructures with a maximum depth of 6 atomic layers.In-situ observation unveils the crystal growth in the form of twinning.High double layer capacitance brings about large number of active sites on the Au thin film and has a logarithmic relationship with mesh grade.Electrochemistry testing shows that the Au MAs perform much better ethanol oxidation reaction than the planar sample;MAs with higher mesh grade have a greater active site utilisation ratio(ASUR),which is important to build electrochemical double layer for efficient charge transfer.Further improvement on ASUR is expected for greater electrocatalytic performance and potential application in direct ethanol fuel cell.展开更多
The mechanisms of energy dissipation are discussed in this paper by reviewing the models and research in atomic-scale friction.The study is undertaken to answer a fundamental question in the study of friction:How is f...The mechanisms of energy dissipation are discussed in this paper by reviewing the models and research in atomic-scale friction.The study is undertaken to answer a fundamental question in the study of friction:How is frictional work dissipated,particularly in cases where material damage and wear are not involved.The initiation of energy dissipation,the role of structural commensurability,and the estimation of the interfacial shear strength have been examined in detail by introducing the Tomlinson model,the Frenkel-Kontorova model,and the cobblestone model,respectively.The discussion is extended to energy dissipation progress described in terms of phononic and electronic damping.The contributions from other mechanisms of dissipation such as viscoelastic relaxation and material wear are also included.As an example,we analyzed a specific process of dissipation in multilayer graphene,on the basis of results of molecular dynamics(MD)simulations,which reveal a reversible part of energy that circulates between the system and the external driver.This leads us to emphasize that it is crucial in future studies to clearly define the coefficient of dissipation.展开更多
Lithium–sulfur(Li–S)batteries have extremely high theoretical energy density that make them as promising systems toward vast practical applications.Expediting redox kinetics of sulfur species is a decisive task to b...Lithium–sulfur(Li–S)batteries have extremely high theoretical energy density that make them as promising systems toward vast practical applications.Expediting redox kinetics of sulfur species is a decisive task to break the kinetic limitation of insulating lithium sulfide/disulfide precipitation/dissolution.Herein,we proposed a porphyrinderived atomic electrocatalyst to exert atomic-efficient electrocatalytic effects on polysulfide intermediates.Quantifying electrocatalytic efficiency of liquid/solid conversion through a potentiostatic intermittent titration technique measurement presents a kinetic understanding of specific phase evolutions imparted by the atomic electrocatalyst.Benefiting from atomically dispersed“lithiophilic”and“sulfiphilic”sites on conductive substrates,the finely designed atomic electrocatalyst endows Li–S cells with remarkable cycling stablity(cyclic decay rate of 0.10%in 300 cycles),excellent rate capability(1035 mAh g−1 at 2 C),and impressive areal capacity(10.9 mAh cm−2 at a sulfur loading of 11.3 mg cm−2).The present work expands atomic electrocatalysts to the Li–S chemistry,deepens kinetic understanding of sulfur species evolution,and encourages application of emerging electrocatalysis in other multielectron/multiphase reaction energy systems.展开更多
The synthesis of atomic-scale metal catalysts is a promising but very challenging project. In this work, we successfully fabricated a hybrid catalyst of PL/Ni（OH）2 with atomic-scale Pt clusters uniformly decorated o...The synthesis of atomic-scale metal catalysts is a promising but very challenging project. In this work, we successfully fabricated a hybrid catalyst of PL/Ni（OH）2 with atomic-scale Pt clusters uniformly decorated on porous Ni（OH）2 nanowires （NWs） via a facile room-temperature synthesis strategy. The as-obtained Ptc/Ni（OH）2 catalyst exhibits highly efficient hydrogen evolution reaction （HER） performance under basic conditions. In 0.1moll-1 KOH, the Ptc/Ni（OH）2 has an onset overpotential of -0 mV vs. RHE, and a significantly low overpotential of 32 mV at a current density of 10mAcm-2, lower than that of the com- mercial 20% Pt/C （58 mV）. The mass current density data illustrated that the PL/Ni（OH）2 reached a high current den- sity of 6.34Amg^-1i at an overpotential of 50 mV, which was approximately 28 times higher than that of the commercial Pt/C （0.223Amg^-1i） at the same overpotential, proving the high-efficiency electrocatalytic activity of the as-obtained Ptc/Ni（OH）2 for HER under alkaline conditions.展开更多
The energy transition and dissipation of atomic-scale friction are investigated using the one-dimensional Prandtl-Tomlinson model.A systematic study of the factors influencing the energy dissipation is conducted,indic...The energy transition and dissipation of atomic-scale friction are investigated using the one-dimensional Prandtl-Tomlinson model.A systematic study of the factors influencing the energy dissipation is conducted,indicating that the energy that accumulated during the stick stage does not always dissipate completely during stick-slip motion.We adopt the energy-dissipation ratio(EDR)to describe the relationship between the energy dissipated permanently in the system and the conservative reversible energy that can be reintroduced to the driving system after the slip process.The EDR can change continuously from 100%to 0,covering the stick-slip,intermediate,and smooth-sliding regimes,depending on various factors such as the stiffness,potential-energy corrugation,damping coefficient,sliding velocity,and the temperature of the system.Among these,the parameterη,which depends on both the surface potential and the lateral stiffness,is proven in this paper to have the most significant impact on the EDR.According toη-T phase diagrams of the EDR,the smooth-sliding superlubricity and thermolubricity are found to be unified with regard to the energy dissipation and transition.An analytical formulation for the EDR that can be used to quantitatively predict the amount of energy dissipation is derived from a lateral-force curve.展开更多
Reversible luminescence modulation behavior upon the photochromic effect endows the photochromic ceramics with 3reat potential in anti-counterfeiting and data storage applications.Here,Sm^(3+)-doped KSr_(2)Nb_(5)O_(15...Reversible luminescence modulation behavior upon the photochromic effect endows the photochromic ceramics with 3reat potential in anti-counterfeiting and data storage applications.Here,Sm^(3+)-doped KSr_(2)Nb_(5)O_(15) photochromic ceramics exhibit superior anti-counterfeiting ability:good covertness and considerable modulation ratio of luminescent emission intensity after photochromic reaction.The results show that the photochromism originated from oxygen and cation vacancies,which were directly identified by electron paramagnetic resonance and positron annihilation lifetime spectra.Unexpectedly,oxygen vacancies work more effectively than cation vacancies during photochromic reactions.Moreover,the extraordinary anti-counterfeiting ability was attributed to the high energy transfer rate,which was particularly caused by the short mean distance below 1 nm between the Sm^(3+) and vacancies.The work here has provided atomic-scale structural evidence and made a progress in understanding the photochromic origins and mechanism in color-center theory.展开更多
Potassium-ion batteries(PIBs)are considered promising alternatives to lithium-ion batteries owing to cost-effective potassium resources and a suitable redox potential of-2.93 V(vs.-3.04 V for Li+/Li).However,the explo...Potassium-ion batteries(PIBs)are considered promising alternatives to lithium-ion batteries owing to cost-effective potassium resources and a suitable redox potential of-2.93 V(vs.-3.04 V for Li+/Li).However,the exploration of appro-priate electrode materials with the correct size for reversibly accommodating large K+ions presents a significant challenge.In addition,the reaction mecha-nisms and origins of enhanced performance remain elusive.Here,tetragonal FeSe nanoflakes of different sizes are designed to serve as an anode for PIBs,and their live and atomic-scale potassiation/depotassiation mechanisms are revealed for the first time through in situ high-resolution transmission electron micros-copy.We found that FeSe undergoes two distinct structural evolutions,sequen-tially characterized by intercalation and conversion reactions,and the initial intercalation behavior is size-dependent.Apparent expansion induced by the intercalation of K+ions is observed in small-sized FeSe nanoflakes,whereas unexpected cracks are formed along the direction of ionic diffusion in large-sized nanoflakes.The significant stress generation and crack extension originating from the combined effect of mechanical and electrochemical interactions are elucidated by geometric phase analysis and finite-element analysis.Despite the different intercalation behaviors,the formed products of Fe and K_(2)Se after full potassiation can be converted back into the original FeSe phase upon depotassiation.In particular,small-sized nanoflakes exhibit better cycling perfor-mance with well-maintained structural integrity.This article presents the first successful demonstration of atomic-scale visualization that can reveal size-dependent potassiation dynamics.Moreover,it provides valuable guidelines for optimizing the dimensions of electrode materials for advanced PIBs.展开更多
Despite the wide availability and usage of Gatan’s DigitalMicrograph software in the electron microscopy community for image recording and analysis, nonlinear least-squares fitting in DigitalMicrograph is less straig...Despite the wide availability and usage of Gatan’s DigitalMicrograph software in the electron microscopy community for image recording and analysis, nonlinear least-squares fitting in DigitalMicrograph is less straightforward. This work presents a ready-to-use tool, the DMPFIT software package, written in DigitalMicrograph script and C++ language, for nonlinear least-squares fitting of the intensity distribution of atomic columns in atomic-resolution transmission electron microscopy (TEM) images with a general two-dimensional (2D) Gaussian model. Applications of the DMPFIT software are demonstrated both in atomic-resolution conventional coherent TEM (CTEM) images recorded by the negative spherical aberration imaging technique and in high angle annular dark field (HAADF) scanning TEM (STEM) images. The implemented peak-finding algorithm based on the periodicity of 2D lattices enables reliable and convenient atomic-scale metrology as well as intuitive presentation of the resolved atomic structures.展开更多
Subject Code:A02With the support by the National Natural Science Foundation of China,an international collaboration involving groups from the University of Science and Technology of China and the University of Manches...Subject Code:A02With the support by the National Natural Science Foundation of China,an international collaboration involving groups from the University of Science and Technology of China and the University of Manchester at the United Kingdom,reported the fabrication of narrow and smooth nanocapillaries through van der Waals assembly with atomic-scale precision.They also studied the water transport through these展开更多
With the support of the National Natural Science Foundation of China,two original studies by the research group led by Prof.Gu Lin(谷林)and Prof.Zhang Qinghua(张庆华)from the Institute of Physics,Chinese Academy of Sc...With the support of the National Natural Science Foundation of China,two original studies by the research group led by Prof.Gu Lin(谷林)and Prof.Zhang Qinghua(张庆华)from the Institute of Physics,Chinese Academy of Sciences demonstrate the in-situ atomic-scale electrically induced展开更多
基金supported by the National Natural Science Foundation of China(52375437,52035009)the Natural Science Foundation of Guangdong Province(2024B1515020027)+2 种基金the Shenzhen Science and Technology Program(Grant No.KQTD20170810110250357)for the financial supportthe assistance of SUSTech Core Research Facilitiessupported by Shenzhen Engineering Research Center for Semiconductorspecific Equipment。
文摘The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method named plasma-based atom-selective etching(PASE)is proposed to achieve the highly efficient,atomic-scale,and damage-free polishing of β-Ga_(2)O_(3).The plasma is excited through the inductive coupling principle and carbon tetrafluoride is utilized as the main reaction gas to etch β-Ga_(2)O_(3).The core of PASE polishing of β-Ga_(2)O_(3)is the remarkable lateral etching effect,which is ensured by both the intrinsic property of the surface and the extrinsic temperature condition.As revealed by density functional theory-based calculations,the intrinsic difference in the etching energy barrier of atoms at the step edge(2.36 eV)and in the terrace plane(4.37 eV)determines their difference in the etching rate,and their etching rate difference can be greatly enlarged by increasing the extrinsic temperature.The polishing of β-Ga_(2)O_(3)based on the lateral etching effect is further verified in the etching experiments.The Sa roughness of β-Ga_(2)O_(3)(001)substrate is reduced from 14.8 nm to 0.057 nm within 120 s,and the corresponding material removal rate reaches up to 20.96μm·min^(−1).The polished β-Ga_(2)O_(3)displays significantly improved crystalline quality and photoluminescence intensity,and the polishing effect of PASE is independent of the crystal face of β-Ga_(2)O_(3).In addition,the competition between chemical etching and physical reconstruction,which is determined by temperature and greatly affects the surface state of β-Ga_(2)O_(3),is deeply studied for the first time.These findings not only demonstrate the high-efficiency and high-quality polishing of β-Ga_(2)O_(3)via atmospheric plasma etching but also hold significant implications for guiding future plasma-based surface manufacturing of β-Ga_(2)O_(3).
文摘The signs of the electric field markers in Figs.2 and 4 of the paper[Chin.Phys.B 32104211(2023)]have been corrected.These modifications do not affect the results derived in the paper.
基金funded by the National Natural Science Foundation of China with Grant No.51425502.
文摘Atomic and close-to-atomic scale manufacturing(ACSM)aims to provide techniques for manufacturing in various fields,such as circuit manufacturing,high energy physics equipment,and medical devices and materials.The realization of atomic scale material manipulation depending on the theoretical system of classical mechanics faces great challenges.Understanding and using intermolecular and surface forces are the basis for better designing of ACSM.Transformation of atoms based on scanning tunneling microscopy or atomic force microscopy(AFM)is an essential process to regulate intermolecular interactions.Self-assemble process is a thermodynamic process involving complex intermolecular forces.The competition of these interaction determines structure assembly and packing geometry.For typical nanomachining processes including AFM nanomachining and chemical mechanical polishing,the coupling of chemistry and stress(tribochemistry)assists in the removal of surface atoms.Furthermore,based on the principle of triboelectrochemistry,we expect a further reduction of the potential barrier,and a potential application in high-efficiency atoms removal and fabricating functional coating.Future fundamental research is proposed for achieving high-efficiency and high-accuracy manufacturing with the aiding of external field.This review highlights the significant contribution of intermolecular and surface forces to ACSM,and may accelerate its progress in the in-depth investigation of fundamentals.
基金supported by the National Natural Science Foundation of China(Grant Nos.51631003 and 51871054)the Fundamental Research Funds for the Central Universities(Grant No.2242019k1G005)supported by the Department of Energy(DOE)Office of Science(DE-AC02-06CH11357)。
文摘The correlation betweent deformation behavior and atomic-scale heterogeneity of bulk metallic glasses(BMGs)is critical to understand the BMGs'deformation mechanism.In this work,three typical[(Fe_(0.5)Co_(0.5))_(0.75)B_(0.2)Si_(0.05)]_(96)Nb_4,Fe_(39)Ni_(39)B_(14.2)Si_(2.75)P_(2.75)Nb_(2.3),and Fe_(50)Ni_(30)P_(13)C_(7)BMGs exhibiting different plasticity were selected,and the correlation between deformation behavior and atomic-scale heterogeneity of Fe-based BMGs was studied.It is found that the serrated flow dynamics of Fe-based BMGs transform from chaotic state to self-organized critical state with increasing plasticity.This transformation is attributed to the increasing atomic-scale heterogeneity caused by the increasing free volume and short-to-medium range order,which facilitates a higher frequency of interaction and multiplication of shear bands,thereby results in a brittle to ductile transition in Fe-based BMGs.This work provides new evidence on heterogeneity in plastic Fe-based BMGs from the aspects of atomic-scale structure,and provides new insight into the plastic deformation of Fe-based BMGs.
基金the financial support from the National Natural Science Foundation of China(Grant Nos.52074257 and 51790484)the Chinese Academy of Sciences(Grant No.ZDBSLY-JSC023)+1 种基金the Liao Ning Revitalization Talents Program(Grant Nos.XLYC1802078 and XLYC1807062)the fund of Qingdao(Grant No.19-9-2-1-wz)。
文摘The intrinsic origins and formation of atomic-scale structure in multicomponent alloys remain largely unknown owing to limited simulations and inaccessible experiments.Herein,we report the formation of three-dimensional periodicity from a disordered atomic-scale structure to an imperfect/perfect ordered cluster and finally to long-range translational and rotational symmetry coupled with Nb heterogeneity.Significant atomic-scale structural clustering and atomic arrangements involving solvent or solute atoms simultaneously occurred during isothermal annealing.A close relationship between atomic-scale structural evolution and composition variation has important implications in depicting the chemical and topological packing during the early crystallization stage in metallic glasses.This work can provide a comprehensive understanding of how short-range orders evolve into long-range periodicity and will further shed light on the origins and nature of metallic glasses.
基金supported by the Key Project of CNSF (No. 50831001)the NSFC (No. 10102001201304)+4 种基金the Beijing Nova Program (Z1511000003150142)the Beijing PXM 201101420409000053 and Beijing 211 ProjectSpecialized Research Fund for the Doctoral Program of Higher Education of China (3C102001201301)The Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality (IDHT20140504)the Australian Research Council (DE150101212)
文摘Nanocrystalline metals have many functional and structural applications due to their excellent mechanical properties compared to their coarse-grained counterparts. The atomic-scale understanding of the deformation mechanisms of nanocrystalline metals is important for designing new materials, novel structures and applications. The review presents recent developments in the methods and techniques for in situ deformation mechanism investigations on face-centered-cubic nanocrystalline metals. In the first part,we will briefly introduce some important techniques that have been used for investigating the deformation behaviors of nanomaterials. Then, the size effects and the plasticity behaviors in nanocrystalline metals are discussed as a basis for comparison with the plasticity in bulk materials. In the last part, we show the atomic-scale and time-resolved dynamic deformation processes of nanocrystalline metals using our in-lab developed deformation device.
基金Project supported by the Guangdong Innovative and Entrepreneurial Research Team Program (Grant No. 2016ZT06C594)the Science and Technology Project of Guangdong Province of China (Grant No. 2020B010190001)+1 种基金the National Key R&D Program of China (Grant No. 2018YFA0306200)the National Natural Science Foundation of China (Grant No. 11974119)。
文摘Atoms in the microscopic world are the basic building blocks of the macroscopic world. In this work, we construct an atomic-scale electromagnetic theory that bridges optics in the microscopic and macroscopic worlds. As the building block of the theory, we use the microscopic polarizability to describe the optical response of a single atom, solve the transport of electromagnetic wave through a single atomic layer under arbitrary incident angle and polarization of the light beam, construct the single atomic layer transfer matrix for light transport across the atomic layer. Based on this transfer matrix, we get the analytical form of the dispersion relation, refractive index, and transmission/reflection coefficient of the macroscopic medium. The developed theory can handle single-layer and few-layers of homogeneous and heterogeneous 2D materials, investigate homogeneous 2D materials with various vacancies or insertion atomic-layer defects, study compound 2D materials with a unit cell composed of several elements in both the lateral and parallel directions with respect to the light transport.
基金the support from the National Natural Science Foundation of China (Grant Nos. 52405447 and 52275299)the National Key Research and Development Program of China (Grant No. 2021YFB1716200)the Key Research and Development Program of Jiangxi Province in China (Grant No. 20232BBE50011)。
文摘Atomic-level manufacturing,as the "keystone" of future technology,marks the transformative shift from the micro/nano era based on "classical theory" to the atomic era grounded in "quantum theory".It enables the precise control of matter arrangement and composition at the atomic scale,thereby achieving large-scale production of atomically precise and structured products.Electrochemical deposition(ECD),a typical "atom addition" fabrication method for electrochemical atomic and close-to-atomic scale manufacturing(EC-ACSM),enables precise control over material properties at the atomic scale,allowing breakthroughs in revolutionary performance of semiconductors,quantum computing,new materials,nanomedicine,etc.This review explores the fundamentals of EC-ACSM,particularly at the electrode/electrolyte interface,and investigates maskless ECD techniques,highlighting their advantages,limitations,and the role of in situ monitoring and advanced simulations in the process optimization.However,atomic electrochemical deposition faces significant challenges in precise control over atom-ion interactions,electrode-electrolyte interfacial dynamics,and surface defects.In the future,overcoming these obstacles is critical to advancing EC-ACSM and unlocking its full potential in scalability for industrial applications.EC-ACSM can drive the highly customized design of materials and offer strong technological support for the development of future science,ushering in a new atomic era of material innovation and device manufacturing.
基金supported by the National Key Research Program of China under Grant No.2021YFB3800601the Basic Science Center Project of the National Natural Science Foundation of China(NSFC)under Grant No.51788104.Min Zhang and Rui Wei contributed equally to this work.
文摘High performance dielectric capacitors are ubiquitous components in the modern electronics industry,owing to the highest power density,fastest charge-discharge rates,and long lifetime.However,the wide application of dielectric capacitors is limited owing to the low energy density.Over the past decades,multiscale structures of dielectric ceramics have been extensively explored and many exciting developments have been achieved.Despite the rapid development of energy storage properties,the atomic structure of dielectric materials is rarely investigated.In this paper,we present a brief overview of how scanning transmission electron microscopy(STEM)is used as a tool to elucidate the morphology,local structure heterogeneity,atomic resolution structure phase evolution and the correlation with energy storage properties,which provides a powerful tool for rational design and synergistic optimization.
基金the MOE AcRF Tier 1 grant M4011528.The XRD and FEG-TEM characterisations were performed at Facility for Analysis,Characterisation,Testing and Simulation(FACTS)Labthe FEG-SEM/FIB characterisations were carried out at Microelectronics Reliability and Characterisation(MRC)Lab.
文摘The catalysis of Au thin film could be improved by fabrication of array structures in large area.In this work,nanoimprint lithography has been developed tofabricate flexible Au micro-array(MA)electrodes with~100%coverage.Advanced electron microscopy characterisations have directly visualised the atomic-scale three-dimensional(3D)nanostructures with a maximum depth of 6 atomic layers.In-situ observation unveils the crystal growth in the form of twinning.High double layer capacitance brings about large number of active sites on the Au thin film and has a logarithmic relationship with mesh grade.Electrochemistry testing shows that the Au MAs perform much better ethanol oxidation reaction than the planar sample;MAs with higher mesh grade have a greater active site utilisation ratio(ASUR),which is important to build electrochemical double layer for efficient charge transfer.Further improvement on ASUR is expected for greater electrocatalytic performance and potential application in direct ethanol fuel cell.
基金The authors would like to express their appreciations to the financial support from the National Natural Science Foundation of China under the grant Nos.of 51075526,51005129,and 51021064.
文摘The mechanisms of energy dissipation are discussed in this paper by reviewing the models and research in atomic-scale friction.The study is undertaken to answer a fundamental question in the study of friction:How is frictional work dissipated,particularly in cases where material damage and wear are not involved.The initiation of energy dissipation,the role of structural commensurability,and the estimation of the interfacial shear strength have been examined in detail by introducing the Tomlinson model,the Frenkel-Kontorova model,and the cobblestone model,respectively.The discussion is extended to energy dissipation progress described in terms of phononic and electronic damping.The contributions from other mechanisms of dissipation such as viscoelastic relaxation and material wear are also included.As an example,we analyzed a specific process of dissipation in multilayer graphene,on the basis of results of molecular dynamics(MD)simulations,which reveal a reversible part of energy that circulates between the system and the external driver.This leads us to emphasize that it is crucial in future studies to clearly define the coefficient of dissipation.
基金This work was supported by the National Key Research and Development Program(2016YFA0202500)National Natural Science Foundation of China(21776019,21808124,and U1801257)We thank Jin Xie and Meng Zhao for their helpful discussion.
文摘Lithium–sulfur(Li–S)batteries have extremely high theoretical energy density that make them as promising systems toward vast practical applications.Expediting redox kinetics of sulfur species is a decisive task to break the kinetic limitation of insulating lithium sulfide/disulfide precipitation/dissolution.Herein,we proposed a porphyrinderived atomic electrocatalyst to exert atomic-efficient electrocatalytic effects on polysulfide intermediates.Quantifying electrocatalytic efficiency of liquid/solid conversion through a potentiostatic intermittent titration technique measurement presents a kinetic understanding of specific phase evolutions imparted by the atomic electrocatalyst.Benefiting from atomically dispersed“lithiophilic”and“sulfiphilic”sites on conductive substrates,the finely designed atomic electrocatalyst endows Li–S cells with remarkable cycling stablity(cyclic decay rate of 0.10%in 300 cycles),excellent rate capability(1035 mAh g−1 at 2 C),and impressive areal capacity(10.9 mAh cm−2 at a sulfur loading of 11.3 mg cm−2).The present work expands atomic electrocatalysts to the Li–S chemistry,deepens kinetic understanding of sulfur species evolution,and encourages application of emerging electrocatalysis in other multielectron/multiphase reaction energy systems.
基金financial support from the National Natural Science Foundation of China(21425103,21673280 and 11374039)
文摘The synthesis of atomic-scale metal catalysts is a promising but very challenging project. In this work, we successfully fabricated a hybrid catalyst of PL/Ni（OH）2 with atomic-scale Pt clusters uniformly decorated on porous Ni（OH）2 nanowires （NWs） via a facile room-temperature synthesis strategy. The as-obtained Ptc/Ni（OH）2 catalyst exhibits highly efficient hydrogen evolution reaction （HER） performance under basic conditions. In 0.1moll-1 KOH, the Ptc/Ni（OH）2 has an onset overpotential of -0 mV vs. RHE, and a significantly low overpotential of 32 mV at a current density of 10mAcm-2, lower than that of the com- mercial 20% Pt/C （58 mV）. The mass current density data illustrated that the PL/Ni（OH）2 reached a high current den- sity of 6.34Amg^-1i at an overpotential of 50 mV, which was approximately 28 times higher than that of the commercial Pt/C （0.223Amg^-1i） at the same overpotential, proving the high-efficiency electrocatalytic activity of the as-obtained Ptc/Ni（OH）2 for HER under alkaline conditions.
基金supported by the National Natural Science Foundation of China(Grant Nos.51422504,51375010,and 51371092)the National Key Basic Research(973)Program of China(No.2013CB934200).
文摘The energy transition and dissipation of atomic-scale friction are investigated using the one-dimensional Prandtl-Tomlinson model.A systematic study of the factors influencing the energy dissipation is conducted,indicating that the energy that accumulated during the stick stage does not always dissipate completely during stick-slip motion.We adopt the energy-dissipation ratio(EDR)to describe the relationship between the energy dissipated permanently in the system and the conservative reversible energy that can be reintroduced to the driving system after the slip process.The EDR can change continuously from 100%to 0,covering the stick-slip,intermediate,and smooth-sliding regimes,depending on various factors such as the stiffness,potential-energy corrugation,damping coefficient,sliding velocity,and the temperature of the system.Among these,the parameterη,which depends on both the surface potential and the lateral stiffness,is proven in this paper to have the most significant impact on the EDR.According toη-T phase diagrams of the EDR,the smooth-sliding superlubricity and thermolubricity are found to be unified with regard to the energy dissipation and transition.An analytical formulation for the EDR that can be used to quantitatively predict the amount of energy dissipation is derived from a lateral-force curve.
基金supported by the China-Poland International Collaboration Fund of National Natural Science Foundation of China(No.51961135301)National Natural Science Foundation of China(No.52072301)+1 种基金the International Cooperation Foundation of Shaanxi Province(No.2019 KW-054,2020 KW-032)the‘111’Project(No.B20028).
文摘Reversible luminescence modulation behavior upon the photochromic effect endows the photochromic ceramics with 3reat potential in anti-counterfeiting and data storage applications.Here,Sm^(3+)-doped KSr_(2)Nb_(5)O_(15) photochromic ceramics exhibit superior anti-counterfeiting ability:good covertness and considerable modulation ratio of luminescent emission intensity after photochromic reaction.The results show that the photochromism originated from oxygen and cation vacancies,which were directly identified by electron paramagnetic resonance and positron annihilation lifetime spectra.Unexpectedly,oxygen vacancies work more effectively than cation vacancies during photochromic reactions.Moreover,the extraordinary anti-counterfeiting ability was attributed to the high energy transfer rate,which was particularly caused by the short mean distance below 1 nm between the Sm^(3+) and vacancies.The work here has provided atomic-scale structural evidence and made a progress in understanding the photochromic origins and mechanism in color-center theory.
基金This work was supported by the National Key R&D Program of China(Grant No.2018YFB1304902)the National Natural Science Foundation of China(Grant Nos.12004034,U1813211,22005247,11904372,51502007,52072323,52122211,12174019,and 51972058)+1 种基金the Gen-eral Research Fund of Hong Kong(Project No.11217221)China Postdoctoral Science Foundation Funded Project(Grant No.2021M690386).
文摘Potassium-ion batteries(PIBs)are considered promising alternatives to lithium-ion batteries owing to cost-effective potassium resources and a suitable redox potential of-2.93 V(vs.-3.04 V for Li+/Li).However,the exploration of appro-priate electrode materials with the correct size for reversibly accommodating large K+ions presents a significant challenge.In addition,the reaction mecha-nisms and origins of enhanced performance remain elusive.Here,tetragonal FeSe nanoflakes of different sizes are designed to serve as an anode for PIBs,and their live and atomic-scale potassiation/depotassiation mechanisms are revealed for the first time through in situ high-resolution transmission electron micros-copy.We found that FeSe undergoes two distinct structural evolutions,sequen-tially characterized by intercalation and conversion reactions,and the initial intercalation behavior is size-dependent.Apparent expansion induced by the intercalation of K+ions is observed in small-sized FeSe nanoflakes,whereas unexpected cracks are formed along the direction of ionic diffusion in large-sized nanoflakes.The significant stress generation and crack extension originating from the combined effect of mechanical and electrochemical interactions are elucidated by geometric phase analysis and finite-element analysis.Despite the different intercalation behaviors,the formed products of Fe and K_(2)Se after full potassiation can be converted back into the original FeSe phase upon depotassiation.In particular,small-sized nanoflakes exhibit better cycling perfor-mance with well-maintained structural integrity.This article presents the first successful demonstration of atomic-scale visualization that can reveal size-dependent potassiation dynamics.Moreover,it provides valuable guidelines for optimizing the dimensions of electrode materials for advanced PIBs.
基金Financial support from the German Research Foundation(SFB917)is acknowledgedOpen Access funding enabled and organized by Projekt DEAL.
文摘Despite the wide availability and usage of Gatan’s DigitalMicrograph software in the electron microscopy community for image recording and analysis, nonlinear least-squares fitting in DigitalMicrograph is less straightforward. This work presents a ready-to-use tool, the DMPFIT software package, written in DigitalMicrograph script and C++ language, for nonlinear least-squares fitting of the intensity distribution of atomic columns in atomic-resolution transmission electron microscopy (TEM) images with a general two-dimensional (2D) Gaussian model. Applications of the DMPFIT software are demonstrated both in atomic-resolution conventional coherent TEM (CTEM) images recorded by the negative spherical aberration imaging technique and in high angle annular dark field (HAADF) scanning TEM (STEM) images. The implemented peak-finding algorithm based on the periodicity of 2D lattices enables reliable and convenient atomic-scale metrology as well as intuitive presentation of the resolved atomic structures.
文摘Subject Code:A02With the support by the National Natural Science Foundation of China,an international collaboration involving groups from the University of Science and Technology of China and the University of Manchester at the United Kingdom,reported the fabrication of narrow and smooth nanocapillaries through van der Waals assembly with atomic-scale precision.They also studied the water transport through these
文摘With the support of the National Natural Science Foundation of China,two original studies by the research group led by Prof.Gu Lin(谷林)and Prof.Zhang Qinghua(张庆华)from the Institute of Physics,Chinese Academy of Sciences demonstrate the in-situ atomic-scale electrically induced
