过渡族与主族元素对Mn_2CoGa能带结构的双调控作用  

The Control Effect of Transition Elements and Main-group Elements on the Band Structure of Mn_2CoGa

作　　者：盘如静 常月华[1] 斯宇豪 王立英[2] 崔玉亭[1] 

机构地区：[1]重庆师范大学物理与电子工程学院,重庆401331 [2]天津大学理学院,天津300072

出　　处：《重庆师范大学学报（自然科学版）》2016年第3期137-141,共5页Journal of Chongqing Normal University:Natural Science

基　　金：国家自然科学基金(No.51271071);重庆市基础与前沿研究项目重点项目(No.cstc2013jjB50001);重庆师范大学博士启动基金(No.13XLB030)

摘　　要：通过第一性原理计算,研究了Mn和Sn双替位掺杂对Heusler结构Mn_2CoGa合金的能带调控作用。结果发现过渡族Mn替换Co元素掺入合金后,对两个自旋方向中的能隙有不同的影响,它能够有效的打开材料中自旋向上能带中的能隙,而对自旋向下能带中的能隙影响较小。主族Sn替换Ga元素掺入后能够极好地调整费米面的位置,并引起材料中原子自旋劈裂的变化。引入Sn元素造成的晶格膨胀则轻微地影响材料中的能隙宽度。通过成分调整,最终在Mn_(2.25)Co_(0.75)Ga_(0.5)Sn_(0.5)成分中,成功发现了自旋无带隙特性。The control effect of Mn and Sn doping on the band structure of Mn2CoGa Heusler alloy has been studied by first-principles calculation.It was found that Mn element doping has different effects on the energy gap in the two spin directions.Mn element doping can greatly open the energy gap in the spin-up channel,while hardly influence on the energy gap in the spin-downone.For Sn element doping,the Fermi surface can be wonderfully adjusted and the change of the spin-splitting can also be caused in this material.At the same time,the lattice expansion caused by Sn doping has a slight influence on the energy gap width of Mn_2CoGa.Finally,the spin-gapless characteristic is successfully developed in Mn_（2.25）Co_（0.75）Ga_（0.5）Sn_（0.5） by the composition adjustment.

关 键 词：第一性原理 HEUSLER合金 半金属材料 自旋无带隙材料 

分 类 号：O482.5[理学—固体物理]