First-principles Study Of Half-Heusler Alloy XYZ(X=Cr,Mn,Fe;Z=S,Se)

Recently,spintronics meet the insatiable demands of the high-tech fields with the rapid development of electronic technology,and half-metal materials with high spin polarization play an important role in the new generation of electronic devices.Generally,the half-metal materials with the Half-Heusler structure possess relatively high Curie temperature and spin polarization.The diverse properties enable them to be promising candidates for spintronics.In this paper,we calculated the electronic structures,magnetic and optical properties of Half-Heusler alloy XYZ(X=Cr,Mn,Fe;Z=S,Se)by VASP which is based on density functional theory and projector augmented wave pseudopotential method.In addition,we also consider the effect of the exchange of atomic positions on the half-metal properties.The main research contents are as follows:Firstly,the structures of Half-Heusler alloy XYZ(X=Cr,Mn,Fe;Z=S,Se)with ferromagnetic,antiferromagnetic and non-magnetic states are optimized to find the most stable structure.On this basis,we calculated and analyzed their electronic structures and magnetic properties.CrYS,MnYS and CrYSe are predicted to have half-metal properties.Secondly,considering the influence of exchanging XYZ's atomic positions(X and Y,Y and Z)on half-metal properties in CrYS,MnYS and CrYSe,we calculated their density of states and analyzed the influence on half-metal properties.Finally,the dielectric function,complex refractive index,absorption coefficient,reflectivity and energy loss spectrum of CrYS,MnYS and CrYSe were calculated,we also analyzed and compared them.