Based on the empirical electronic theory of solids and molecules （EET）, the actual model for unit cell of cementite （0-FeaC） was built and the valence electron structures （VES） of cementite with specified site a...Based on the empirical electronic theory of solids and molecules （EET）, the actual model for unit cell of cementite （0-FeaC） was built and the valence electron structures （VES） of cementite with specified site and a number of Fe atoms substituted by alloying atoms of M （ M=Cr, V, W, Mo, Mn ） were computed by statistical method. By defining P as the stability factor, the stability of alloyed cementite with different numbers and sites of Fe atoms substituted by M was calculated. Calculation results show that the density of lattice electrons, the symmetry of distribution of covalent electron pairs and bond energy have huge influence on the stability of alloyed cementite. It is more stable as M substitutes for FeE than for Fe1. The alloyed cementite is the most stable when Cr, Mo, W and V substitute for 2 atoms of Fe2 at the sites of Nos. 2 and 3 （or No. 6 and No. 7）. The stability of alloyed cementite decreases gradually as being substitutional doped by W, Cr, V, Mo and Mn.展开更多
Despite extensive research on recently discovered layered ferromagnetic(FM)materials,their further development is hampered by the limited number of candidate materials with desired properties.As a much bigger family,l...Despite extensive research on recently discovered layered ferromagnetic(FM)materials,their further development is hampered by the limited number of candidate materials with desired properties.As a much bigger family,layered antiferromagnetic(AFM)materials represent excellent platforms to not only deepen our understanding of fundamental physics but also push forward high-performance spintronics applications.Here,by systematic first-principles calculations,we demonstrate pressure and carrier doping control of magnetic properties in layered AFM CoPS3,a representative of transition metal phosphorus trichalcogenides.In particular,pressure can drive isostructural Mott transition,in sharp contrast to other transition metal thiophosphates.Intriguingly,both pressure and carrier doping can realize the long-sought FM half-metallic states with 100%spin polarization percentage,which is good for improving the injection and detection efficiency of spin currents among others.Moreover,the Mott transition is accompanied by instantaneous spin-crossover(SCO)in CoPS3,and such cooperative SCO facilitates the implementation of fast-response reversible devices,such as data storage devices,optical displays and sensors.We further provide an in-depth analysis for the mechanisms of FM half-metallicity and SCO.Tunable magnetism in layered AFM materials opens vast opportunities for purposeful device design with various functionalities.展开更多
基金Project(2014CFB801)supported by Natural Science Foundation of Hubei Province of ChinaProject(11304236)supported by the National Natural Science Foundation of China
文摘Based on the empirical electronic theory of solids and molecules （EET）, the actual model for unit cell of cementite （0-FeaC） was built and the valence electron structures （VES） of cementite with specified site and a number of Fe atoms substituted by alloying atoms of M （ M=Cr, V, W, Mo, Mn ） were computed by statistical method. By defining P as the stability factor, the stability of alloyed cementite with different numbers and sites of Fe atoms substituted by M was calculated. Calculation results show that the density of lattice electrons, the symmetry of distribution of covalent electron pairs and bond energy have huge influence on the stability of alloyed cementite. It is more stable as M substitutes for FeE than for Fe1. The alloyed cementite is the most stable when Cr, Mo, W and V substitute for 2 atoms of Fe2 at the sites of Nos. 2 and 3 （or No. 6 and No. 7）. The stability of alloyed cementite decreases gradually as being substitutional doped by W, Cr, V, Mo and Mn.
基金the National Key Research and Development Program of China(2017YFB0701600)the National Natural Science Foundation of China(11974197 and 51920105002)+2 种基金Guangdong Innovative and Entrepre-neurial Research Team Program(2017ZT07C341)China Postdoctoral Science Foundation(2018M631458)the Bureau of Industry and Information Technology of Shenzhen for the 2017 Graphene Manufacturing Innovation Center Project(201901171523)。
文摘Despite extensive research on recently discovered layered ferromagnetic(FM)materials,their further development is hampered by the limited number of candidate materials with desired properties.As a much bigger family,layered antiferromagnetic(AFM)materials represent excellent platforms to not only deepen our understanding of fundamental physics but also push forward high-performance spintronics applications.Here,by systematic first-principles calculations,we demonstrate pressure and carrier doping control of magnetic properties in layered AFM CoPS3,a representative of transition metal phosphorus trichalcogenides.In particular,pressure can drive isostructural Mott transition,in sharp contrast to other transition metal thiophosphates.Intriguingly,both pressure and carrier doping can realize the long-sought FM half-metallic states with 100%spin polarization percentage,which is good for improving the injection and detection efficiency of spin currents among others.Moreover,the Mott transition is accompanied by instantaneous spin-crossover(SCO)in CoPS3,and such cooperative SCO facilitates the implementation of fast-response reversible devices,such as data storage devices,optical displays and sensors.We further provide an in-depth analysis for the mechanisms of FM half-metallicity and SCO.Tunable magnetism in layered AFM materials opens vast opportunities for purposeful device design with various functionalities.
