The US President Obama launched the Materials Genome Initiative on June 24,2011,aimed at speeding up the pace of discovering,developing,manufacturing,and deploying advanced materials by at least twice as fast as is po...The US President Obama launched the Materials Genome Initiative on June 24,2011,aimed at speeding up the pace of discovering,developing,manufacturing,and deploying advanced materials by at least twice as fast as is possible at present,at a fraction of the cost with the help of existing advanced computer technology.According to the authors’understanding to the event,this article will first give a brief discussion on the origin of material genome,its scientific implication,research significance,and the far-reaching influence of materials genome study to the developments of materials science and human society.Then,the subsequent contents will introduce the research progresses of the related works carried out by the authors’research group over the last decade,on the first-principles studies of crystalline materials genome.The highlights are focused on the method implementations for configuration optimization of lattice structure,first-principles calculations of various physical parameters on elastic,electronic,dielectric,and thermodynamic properties,and simulations of phase transition and particle transport in solids.The technical details for extending these methods to low-dimensional crystalline materials are also discussed.The article concludes with an outlook on the prospect of materials genome research.展开更多
Manipulation of valley pseudospins is crucial for future valleytronics. lhe emerging transition metal dichalcogenides （TMDs） provide new possibilities for exploring the interplay among the quantum degrees of freedom...Manipulation of valley pseudospins is crucial for future valleytronics. lhe emerging transition metal dichalcogenides （TMDs） provide new possibilities for exploring the interplay among the quantum degrees of freedom, including real spin, valley pseudospin, and layer pseudospin. For example, spin-valley coupling results in valley-dependent circular dichroism in which electrons with particular spin （up or down） can be selectively excited by chiral optical pumping in monolayer TMDs, whereas in few-layer TMDs, the interlayer hopping further affects the spin-valley coupling. In addition to valley and layer pseudospins, here we propose a new degree of freedom--stacking pseudospin--and demonstrate new phenomena correlated to this new stacking freedom that otherwise require the application of external electrical or magnetic field. We investigated all possible stacking configurations of chemical-vapor-deposition-grown trilayer MoS2 （AAA, ABB, AAB, ABA, and 3R）. Although the AAA, ABA, 3R stackings possess a sole peak with lower degree of valley polarization than that in monolayer samples, the AAB （ABB） stackings exhibit two distinct peaks, one similar to that observed in monolayer MoS2 and findings provide a more future valleytronics. an additional unpolarized complete understanding of peak at lower energy. Our valley quantum control for展开更多
Lattice defects are unavoidable structural units in materials and play an important role in determining material properties.Compared with the periodic structure of crystals,the atomic configurations of the lattice def...Lattice defects are unavoidable structural units in materials and play an important role in determining material properties.Compared with the periodic structure of crystals,the atomic configurations of the lattice defects are determined by the coordinates of a large number of atoms,making it difficult to experimentally investigate them.In computational materials science,multiparameter optimization is also a difficult problem and experimental verification is usually required to determine the possibility of obtaining the structure and properties predicted by calculations.Using our recent studies on oxide surfaces as examples,we introduce the method of integrated aberration-corrected electron microscopy and the first-principles calculations to analyze the atomic structure of lattice defects.The atomic configurations of defects were measured using quantitative high-resolution electron microscopy at subangstrom resolution and picometer precision,and then the electronic structure and dynamic behavior of materials can be studied at the atomic scale using the firstprinciples calculations.The two methods complement each other and can be combined to increase the understanding of the atomic structure of materials in both the time and space dimensions,which will benefit materials design at the atomic scale.展开更多
We investigate the segregation behavior of alloying atoms （Sr, Th, In, Cd, Ag, Sc, Au, Zn, Cu, Mn, Cr, and Ti） near Z3 （ 111 ） [1]-0] tilt symmetric grain boundary （GB） in tungsten and their effects on the inter...We investigate the segregation behavior of alloying atoms （Sr, Th, In, Cd, Ag, Sc, Au, Zn, Cu, Mn, Cr, and Ti） near Z3 （ 111 ） [1]-0] tilt symmetric grain boundary （GB） in tungsten and their effects on the intergranular embrittlement by performing first-principles calculations. The calculated segregation energies suggest that Ag, Au, Cd, In, Sc, Sr, Th, and Ti prefer to occupy the site in the mirror plane of the GB, while Cu, Cr, Mn, and Zn intend to locate at the first layer nearby the GB core. The calculated strengthening energies predict Sr, Th, In, Cd, Ag, Sc, Au, Ti, and Zn act as embrittlers while Cu, Cr, and Mn act as cohesion enhancers. The correlation of the alloying atom＇s metal radius with strengthening energy is strong enough to predict the strengthening and embrittling behavior of alloying atoms; that is, the alloying atom with larger metal radius than W acts as an embrittler and the one with smaller metal radius acts as a cohesion enhancer.展开更多
The author’s perspective on Materials Genome is presented in this paper through several related projects.Current thermodynamic and kinetic databases of multicomponent materials consist of Gibbs energy functions and a...The author’s perspective on Materials Genome is presented in this paper through several related projects.Current thermodynamic and kinetic databases of multicomponent materials consist of Gibbs energy functions and atomic mobility of individual phases as functions of temperature,composition,and sometimes pressure,i.e.,with the individual phases based on crystal structures as the genome(building blocks)of materials.It is articulated that if an individual phase has its internal configurations,such as magnetic spin configurations and ferroelectric polarization,change significantly with respect to temperature,stress,and magnetic and electric fields,then those individual configurations instead should be considered as the genome of the individual phase.The‘‘mutation’’of an individual phase is governed by the entropy of mixing among the individual stable and metastable configurations,named as microstate configurational entropy,and responsible to anomalies in individual phases.Our ability to tailor the properties of those individual configurations as a function of compositions is the key for the design of materials.展开更多
基金supported by the National Basic Research Program of China(2006CB605103,2011CB606403)the National Natural Science Foundation of China(50072035,50472085,51071149)
文摘The US President Obama launched the Materials Genome Initiative on June 24,2011,aimed at speeding up the pace of discovering,developing,manufacturing,and deploying advanced materials by at least twice as fast as is possible at present,at a fraction of the cost with the help of existing advanced computer technology.According to the authors’understanding to the event,this article will first give a brief discussion on the origin of material genome,its scientific implication,research significance,and the far-reaching influence of materials genome study to the developments of materials science and human society.Then,the subsequent contents will introduce the research progresses of the related works carried out by the authors’research group over the last decade,on the first-principles studies of crystalline materials genome.The highlights are focused on the method implementations for configuration optimization of lattice structure,first-principles calculations of various physical parameters on elastic,electronic,dielectric,and thermodynamic properties,and simulations of phase transition and particle transport in solids.The technical details for extending these methods to low-dimensional crystalline materials are also discussed.The article concludes with an outlook on the prospect of materials genome research.
文摘Manipulation of valley pseudospins is crucial for future valleytronics. lhe emerging transition metal dichalcogenides （TMDs） provide new possibilities for exploring the interplay among the quantum degrees of freedom, including real spin, valley pseudospin, and layer pseudospin. For example, spin-valley coupling results in valley-dependent circular dichroism in which electrons with particular spin （up or down） can be selectively excited by chiral optical pumping in monolayer TMDs, whereas in few-layer TMDs, the interlayer hopping further affects the spin-valley coupling. In addition to valley and layer pseudospins, here we propose a new degree of freedom--stacking pseudospin--and demonstrate new phenomena correlated to this new stacking freedom that otherwise require the application of external electrical or magnetic field. We investigated all possible stacking configurations of chemical-vapor-deposition-grown trilayer MoS2 （AAA, ABB, AAB, ABA, and 3R）. Although the AAA, ABA, 3R stackings possess a sole peak with lower degree of valley polarization than that in monolayer samples, the AAB （ABB） stackings exhibit two distinct peaks, one similar to that observed in monolayer MoS2 and findings provide a more future valleytronics. an additional unpolarized complete understanding of peak at lower energy. Our valley quantum control for
基金supported by the National Basic Research Program of China(2009CB623701,2011CB606406)the National Natural Science Foundation of China(51371102,51390475,51071092,11374174,and 51390471)+2 种基金the Foundation for the Author of National Excellent Doctoral Dissertation of Chinathe Program for New Century Excellent Talents in Universitythe Scientific Foundation for Returned Overseas Chinese Scholars,Ministry of Education
文摘Lattice defects are unavoidable structural units in materials and play an important role in determining material properties.Compared with the periodic structure of crystals,the atomic configurations of the lattice defects are determined by the coordinates of a large number of atoms,making it difficult to experimentally investigate them.In computational materials science,multiparameter optimization is also a difficult problem and experimental verification is usually required to determine the possibility of obtaining the structure and properties predicted by calculations.Using our recent studies on oxide surfaces as examples,we introduce the method of integrated aberration-corrected electron microscopy and the first-principles calculations to analyze the atomic structure of lattice defects.The atomic configurations of defects were measured using quantitative high-resolution electron microscopy at subangstrom resolution and picometer precision,and then the electronic structure and dynamic behavior of materials can be studied at the atomic scale using the firstprinciples calculations.The two methods complement each other and can be combined to increase the understanding of the atomic structure of materials in both the time and space dimensions,which will benefit materials design at the atomic scale.
基金Project supported by the National Magnetic Confinement Fusion Program(Grant No.2011GB108004)the National Natural Science Foundation of China(Grant Nos.91026002 and 91126002)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.KJCX2-YW-N35 andXDA03010303)the Center for Computation Science,Hefei Institutes of Physical Sciences
文摘We investigate the segregation behavior of alloying atoms （Sr, Th, In, Cd, Ag, Sc, Au, Zn, Cu, Mn, Cr, and Ti） near Z3 （ 111 ） [1]-0] tilt symmetric grain boundary （GB） in tungsten and their effects on the intergranular embrittlement by performing first-principles calculations. The calculated segregation energies suggest that Ag, Au, Cd, In, Sc, Sr, Th, and Ti prefer to occupy the site in the mirror plane of the GB, while Cu, Cr, Mn, and Zn intend to locate at the first layer nearby the GB core. The calculated strengthening energies predict Sr, Th, In, Cd, Ag, Sc, Au, Ti, and Zn act as embrittlers while Cu, Cr, and Mn act as cohesion enhancers. The correlation of the alloying atom＇s metal radius with strengthening energy is strong enough to predict the strengthening and embrittling behavior of alloying atoms; that is, the alloying atom with larger metal radius than W acts as an embrittler and the one with smaller metal radius acts as a cohesion enhancer.
基金supported by the National Science Foundation(DMR-1006557)the National Energy Technology Lab(2010-SC-RES-30033026)+1 种基金the Army Research Lab(W911NF-08-2-0064)the Office of Navy Research Office(N0014-07-1-0638)
文摘The author’s perspective on Materials Genome is presented in this paper through several related projects.Current thermodynamic and kinetic databases of multicomponent materials consist of Gibbs energy functions and atomic mobility of individual phases as functions of temperature,composition,and sometimes pressure,i.e.,with the individual phases based on crystal structures as the genome(building blocks)of materials.It is articulated that if an individual phase has its internal configurations,such as magnetic spin configurations and ferroelectric polarization,change significantly with respect to temperature,stress,and magnetic and electric fields,then those individual configurations instead should be considered as the genome of the individual phase.The‘‘mutation’’of an individual phase is governed by the entropy of mixing among the individual stable and metastable configurations,named as microstate configurational entropy,and responsible to anomalies in individual phases.Our ability to tailor the properties of those individual configurations as a function of compositions is the key for the design of materials.
基金supported by the National Natural Science Foundation of China(T2225013,12174142,11904142,and 11534003)the Program for Jilin University Science and Technology Innovative Research Team(2021TD–05)。
