La掺杂ZnS的电子结构与稳定性的研究

Study on Electronic Structure and Stability of La-doped ZnS

采用第一性原理赝势平面波方法研究了La掺杂ZnS体系的电子结构与稳定性。通过对掺杂前后各模型的形成热、结合能、能带结构、态密度、Mulliken电荷和键重叠聚居数的计算与分析,结果表明:La置换ZnS中的Zn是许可的,且能够稳定存在;La原子较Zn原子具有较强的失电子能力,La原子的掺入,对ZnS体系具有共价键与离子键的共同作用;导致体系能带结构发生明显变化,禁带宽度变小,系统发生Mott转变,从半导体变为金属;原子半径较大的La原子致使其周围的电子分布表现出一定的各向异性。

Electronic structure and stability of La-doped ZnS were studied by the first princi- ple plane-wave pseudopotential method. The systematic investigation on formation heat, cohesive energies, energy band structure, state density, mulliken charge and bond overlap population of ZnS with and without La-doping had been performed. Calculation results showed that displace- ment reaction of Zn by La in La-doped ZnS was allowed and exist stably. La atoms owned larger ability of lossing electrons than that of Zn atoms. Thus, covalent bonds and ionic bonds both ex- ist in La-doped ZnS systems. La-doping narrowed the band gap of ZnS systems. La doped ZnS system changed from semiconductor into metal through the Mott transition. Due to larger atom radius of La than that of Zn, anisotropy of electron distribution around La atom was depicted.