Heusler合金Sc_2VZ(Z=C,Si,Ge,Sn,Pb)半金属铁磁性的第一性原理研究  

Half-metallic Ferromagnetism of Heusler Compounds Sc_2VZ(Z=C,Si,Ge,Sn,Pb):a First-principle Study

作　　者：刘兴军[1] 王正伟[1] 许伟伟[1] 韩佳甲[1] 王翠萍[1] 

机构地区：[1]厦门大学材料学院,福建厦门361005

出　　处：《厦门大学学报（自然科学版）》2014年第5期750-758,共9页Journal of Xiamen University：Natural Science

基　　金：国家自然科学基金重点项目(50971109)

摘　　要：采用基于密度泛函理论(DFT)第一性原理的投影缀加波方法 (PAW),结合广义梯度近似(GGA),系统研究了Hg2CuTi型Heusler合金Sc2VZ(Z=C,Si,Ge,Sn,Pb)的电子结构和磁性.研究发现Heusler合金Sc2VZ(Z=Si,Ge,Sn,Pb)在平衡晶格常数下表现出半金属铁磁性,其自旋向上态中的带隙宽度分别为0.345,0.354,0.387和0.173eV.计算得到Sc2VZ(Z=Si,Ge,Sn,Pb)的总自旋磁矩均为整数(3.00μB),符合Slater-Pauling规则.分析能带与态密度发现,半金属带隙的产生主要是由于Sc和V原子d态电子之间强烈的杂化作用所致.同时计算结果也表明,在一定程度的晶格常数变化范围内,Sc2VZ(Z=Si,Ge,Sn,Pb)合金仍能保持其半金属性质.Half-metallic properties of new Sc-based full Heusler compounds Sc2VZ （Z = C, Si, Ge, Sn, Pb） with Hg2 CuTi-prototype structure are systematically investigated using first-principles calculations within generalized gradient approximation （GGA）. It is predicted that all the Sc2VZ Heusler compounds are half-metallic ferromagnets,except for Sc2VC. The calculated band gaps of majori- ty spin states are 0. 345,0. 354,0. 387 and 0. 173 eV for Sc2VSi, Sc2VGe, Sc2VSn and Sc2VPb, respectively. The total magnetic mo- ments of Sc2VZ （Z= Si,Ge,Sn,Pb） compounds are found to be 3.00μB per formula unit,which accords with the Slater Pauling rule Mtot= 18--Z1 between the total magnetic moment （Mtot） and the total number of valence electrons （Z1） per unit cell. Moreover, the origin of half-metallic majority band gaps has been discussed in terms of band structures and density of states for Sc2VZ （Z=Si,Ge, Sn, Pb） compounds. It is found that the half-metallicity can be maintained within a relatively wide range of lattice constants for Sc2VZ （Z=Si,Ge,Sn,Pb） compounds.

关 键 词：第一性原理 半金属铁磁性 HEUSLER合金 电子结构 磁性 

分 类 号：O469[理学—凝聚态物理]