中文摘要：

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.

英文摘要：

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.