Two-dimensional(2D) atomic crystals,such as graphene,black phosphorus(BP) and transition metal dichalcogenides(TMDCs) are attractive for use in optoelectronic devices,due to their unique crystal structures and optical...Two-dimensional(2D) atomic crystals,such as graphene,black phosphorus(BP) and transition metal dichalcogenides(TMDCs) are attractive for use in optoelectronic devices,due to their unique crystal structures and optical absorption properties.In this study,we fabricated BP/ReS2 van der Waals(vdWs) heterojunction devices.The devices realized broadband photoresponse from visible to near infrared(NIR)(400–1800 nm) with stable and repeatable photoswitch characteristics,and the photoresponsivity reached 1.8 mA/W at 1550 nm.In addition,the polarization sensitive detection in the visible to NIR spectrum(532–1750 nm) was demonstrated,and the photodetector showed a highly polarization sensitive photocurrent with an anisotropy ratio as high as 6.44 at 1064 nm.Our study shows that van der Waals heterojunction is an effective way to realize the broadband polarization sensitive photodetection,which is of great significance to the realization and application of multi-functional devices based on 2D vdWs heterostructures.展开更多
Different than covalently bonded magnetic multilayer systems,high-quality interfaces without dangling bonds in van der Waals(vd W)junctions of two-dimensional(2D)layered magnetic materials offer opportunities to reali...Different than covalently bonded magnetic multilayer systems,high-quality interfaces without dangling bonds in van der Waals(vd W)junctions of two-dimensional(2D)layered magnetic materials offer opportunities to realize novel functionalities.Here,we report the fabrication of multi-state vertical spin valves without spacer layers by using vd W homo-junctions in which exfoliated Fe3GeTe2 nanoflakes act as ferromagnetic electrodes and/or interlayers.We demonstrate the typical behavior of two-state and threestate magnetoresistance for devices with two and three Fe3GeTe2 nanoflakes,respectively.Distinct from traditional spin valves with sandwich structures,our novel homo-junction-based spin-valve structure allows the straightforward realization of multi-state magnetic devices.Our work demonstrates the possibility of extend multi-state,non-volatile spin information to 2 D magnetic homo-junctions,and it emphasizes the utility of vd W interface as a fundamental building block for spintronic devices.展开更多
In the past a few years,there has been significant progress in theoretical characterizations of gas-surface reaction dynamics at the atomic level.One of the major breakthroughs is the machine learning representations ...In the past a few years,there has been significant progress in theoretical characterizations of gas-surface reaction dynamics at the atomic level.One of the major breakthroughs is the machine learning representations of the potential energy surfaces and related properties for molecules on metal surfaces from first-principles,particularly neural networks based methods.In this review,we focus on recent advances of the development and applications of high-dimensional symmetry-preserving neural network representations in gas-surface systems,which have enabled efficient Born-Oppenheimer molecular dynamics simulations with inclusion of all molecular and surface degrees of freedom,as well as some nonadiabatic molecular dynamics simulations with effective treatment of hot electrons,at the density function theory level.Despite these advances,further challenges remain.More accurate electronic structure theories and more efficient machine learning(and active learning)algorithms are needed towards a more quantitative description of more complex gas-surface reactions involving multiple surfaces and adsorbates or multiple electronic states.展开更多
基金supported by the National Key R&D Program of China (Grant No. 2017YFA0303400 and No.2017YFB 0405700)supported by the NSFC Grant Nos. 61774144 and 11474272sponsored by Chinese Academy of Sciences, grant No. QYZDY-SSW-JSC020, XDPB12, and XDB28000000
文摘Two-dimensional(2D) atomic crystals,such as graphene,black phosphorus(BP) and transition metal dichalcogenides(TMDCs) are attractive for use in optoelectronic devices,due to their unique crystal structures and optical absorption properties.In this study,we fabricated BP/ReS2 van der Waals(vdWs) heterojunction devices.The devices realized broadband photoresponse from visible to near infrared(NIR)(400–1800 nm) with stable and repeatable photoswitch characteristics,and the photoresponsivity reached 1.8 mA/W at 1550 nm.In addition,the polarization sensitive detection in the visible to NIR spectrum(532–1750 nm) was demonstrated,and the photodetector showed a highly polarization sensitive photocurrent with an anisotropy ratio as high as 6.44 at 1064 nm.Our study shows that van der Waals heterojunction is an effective way to realize the broadband polarization sensitive photodetection,which is of great significance to the realization and application of multi-functional devices based on 2D vdWs heterostructures.
基金supported by the National Key R&D Program of China (2017YFA0303400 and 2017YFB0405700)the National Natural Science foundation of China (61774144)+2 种基金Beijing Natural Science Foundation Key Program (Z190007)the Project from Chinese Academy of Sciences (QYZDY-SSW-JSC020, XDPB12, and XDB28000000)K C Wong Education Foundation。
文摘Different than covalently bonded magnetic multilayer systems,high-quality interfaces without dangling bonds in van der Waals(vd W)junctions of two-dimensional(2D)layered magnetic materials offer opportunities to realize novel functionalities.Here,we report the fabrication of multi-state vertical spin valves without spacer layers by using vd W homo-junctions in which exfoliated Fe3GeTe2 nanoflakes act as ferromagnetic electrodes and/or interlayers.We demonstrate the typical behavior of two-state and threestate magnetoresistance for devices with two and three Fe3GeTe2 nanoflakes,respectively.Distinct from traditional spin valves with sandwich structures,our novel homo-junction-based spin-valve structure allows the straightforward realization of multi-state magnetic devices.Our work demonstrates the possibility of extend multi-state,non-volatile spin information to 2 D magnetic homo-junctions,and it emphasizes the utility of vd W interface as a fundamental building block for spintronic devices.
基金supported by the National Key R&D Program of China(2017YFA0303500)the National Natural Science Foundation of China(22073089 and 22033007)+1 种基金Anhui Initiative in Quantum Information Technologies(AHY090200)The Fundamen-tal Research Funds for the Central Universities(WK2060000017)。
文摘In the past a few years,there has been significant progress in theoretical characterizations of gas-surface reaction dynamics at the atomic level.One of the major breakthroughs is the machine learning representations of the potential energy surfaces and related properties for molecules on metal surfaces from first-principles,particularly neural networks based methods.In this review,we focus on recent advances of the development and applications of high-dimensional symmetry-preserving neural network representations in gas-surface systems,which have enabled efficient Born-Oppenheimer molecular dynamics simulations with inclusion of all molecular and surface degrees of freedom,as well as some nonadiabatic molecular dynamics simulations with effective treatment of hot electrons,at the density function theory level.Despite these advances,further challenges remain.More accurate electronic structure theories and more efficient machine learning(and active learning)algorithms are needed towards a more quantitative description of more complex gas-surface reactions involving multiple surfaces and adsorbates or multiple electronic states.
