CuHg_2Ti型Ti_2Cr基合金的电子结构、能隙起源和磁性研究  

Electronic structures, band-gap origins and magnetisms of Ti_2Cr-based alloys with CuHg_2Ti-type structure

作　　者：贾红英[1,2] 代学芳[1] 王立英[1] 刘然[1] 王啸天[1] 李朋朋[1] 崔玉亭[2] 王文洪[3] 吴光恒[3] 刘国栋[1,2] 

机构地区：[1]河北工业大学材料科学与工程学院,天津300130 [2]重庆师范大学物理与电子工程学院,重庆400044 [3]中国科学院物理研究所北京凝聚态物理国家实验室,北京100190

出　　处：《物理学报》2014年第10期350-359,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51271071;11074160);教育部新世纪优秀人才支持计划(批准号:NCET-10-0126);河北省应用基础研究计划重点基础研究项目(批准号:12965136D);河北省自然科学基金(批准号:E2013202181);河北省高等学校科学技术研究青年基金(批准号:Q2012008)资助的课题~~

摘　　要：利用第一性原理计算方法,研究了CuHg2Ti结构下Ti2CrK(K=Sb,Ge,Sn,Sb,Bi)系列合金的电子结构、能隙起源和磁性.研究发现:Ti2CrK(K=Si,Ge)合金是普通半导体材料;Ti2CrK(K=Si,Bi)合金是亚铁磁性半金属材料,其半金属性能隙受到Sb和Bi原子s态的直接影响;Ti2CrSn合金是完全补偿的亚铁磁性半导体.基于Ti2CrSn合金两个自旋方向上的能隙起源不同,通过Si和Ge替换掺杂同族Sn元素调制能隙的宽度,获得了完全补偿亚铁磁性自旋无能隙材料;通过Fe和Mn替换掺杂过渡族Cr元素获得了一系列半金属材料.Ti2Cr1-xFexSn和Ti2Cr1-xMnxSn合金都具有亚铁磁性.所研究的这些半金属性合金的分子磁矩Mtotal与总的价电子数Zt服从Mtotal=Zt-18规则.The electronic structures, band-gap origins and magnetisms of Ti2Cr-based alloys with CuHg2Ti-type structure are studied using the first principles calculations. It is found that Ti2CrK （K = Si, Ge） alloys are semiconductors Ti2CrK （K = Sb, Bi） alloys are predicted to be half-metallic ferrimagnets and their half-metallic band gaps are affected directly by the S states of Sb and Bi atoms. Ti2CrSn alloy is a completely-compensated ferrimagnetic semiconductor. Due to the different band-gap origins of Ti2CrSn alloy in two spin directions, we can adjust the width of band gap by doping engineering. The ferrimagnetic spin-gapless materials are achieved by substituting Si or Ge for Sn. Substituting Fe or Mn for Cr, we gain a series of half-metallic materials. Ti2Cr1-xFexSn and Ti2Cr1-xMnxSn alloys are in ferrimagnetic states. All the half-metallic Ti2Cr-based alloys follow Mtotal =Zt - 18 rule （Mtotal is the total magnetic moment and Zt is the valence concentration）.

关 键 词：HEUSLER合金 半金属材料 自旋无能隙材料 

分 类 号：O469[理学—凝聚态物理]