Heusler合金Mn_(2)CoAl(100)的表面结构和电磁性质  

Surface Structure and Electromagnetic Properties of Heusler Alloy Mn_(2)CoAl(100)

作　　者：文林 江玲 顾玉鑫 杜信 沈光先[1] 吴波 WEN Lin;JIANG Ling;GU Yuxin;DU Xin;SHEN Guangxian;WU Bo(School of Physics and Electronic Science,Guizhou Normal University,Guiyang 550025,China;School of Physics and Electronic Science,Zunyi Normal University,Zunyi 563006,China)

机构地区：[1]贵州师范大学物理与电子科学学院,贵阳550025 [2]遵义师范学院物理与电子科学学院,遵义563006

出　　处：《人工晶体学报》2025年第4期636-642,共7页Journal of Synthetic Crystals

基　　金：国家自然科学基金(12264060);贵州省教育厅自然科学创新群体项目(黔教合KY字〔2020〕025)。

摘　　要：本文采用第一性原理计算,系统地研究了Heusler合金Mn_(2)CoAl块体的磁性及Mn_(2)CoAl(100)表面的原子弛豫、磁性、电子结构和表面原子极化行为。原子弛豫计算显示,MnAl端面呈现层间差异化位移特征,第一层Mn原子向端面内部弛豫而Al原子向真空层外移,第二层原子均向真空层移动,第三层原子则呈现内缩趋势;其余三种MnCo、MnMn和CoCo端面则表现出相似规律,其三层原子均向真空层外略微移动,四种端面的整体结构均未发生显著形变。在Mn_(2)CoAl(100)不同原子端面中,MnCo和CoCo端面的半金属带隙被表面态破坏,而MnAl和MnMn端面未受到表面态的明显影响,半金属带隙较大,分别保留了约92%和80%的极化率,预测其在隧道异质结中可能具有较好的应用潜力。In this paper,the magnetic properties of Heusler alloy Mn_(2)CoAl bulk and the atomic relaxation,magnetism,electronic structure and surface atomic polarization behavior of Mn_(2)CoAl(100)surface were systematically studied by first-principles calculations.Atomic relaxation calculations reveal that the MnAl termination exhibits interlayer differential displacement characteristics:Mn atoms in the first layer relax inward toward the termination while Al atoms shift outward toward the vacuum layer,atoms in the second layer collectively migrate toward the vacuum layer,and those in the third layer display an inward contraction tendency.The remaining three terminations,MnCo,MnMn and CoCo,follow similar patterns,with all three atomic layers in each termination showing slight outward displacements toward the vacuum layer.Notably,no significant deformation occurs in the overall structures of all four terminations.The half-metallic gaps at the MnCo and CoCo terminations of Mn_(2)CoAl(100)are destroyed by the surface state,while the MnAl and MnMn terminations are not significantly affected and have larger half-metallic gaps,retaining about 92%and 80%of the polarization,respectively,which is predicted to have a superior potential for possible applications in tunnel junctions.

关 键 词：HEUSLER合金 Mn_(2)CoAl 半金属性 表面 磁性 隧道异质结 

分 类 号：O469[理学—凝聚态物理]