PbTe(001)表面原子几何结构和电子结构的第一性原理计算  

First-principles calculations on the geometry and the electronic structure of PbTe(001) surface

作　　者：马健新[1] 贾瑜[1] 梁二军[1] 王晓春[1] 王飞[1] 胡行[1] 

机构地区：[1]郑州大学物理工程学院,郑州450052

出　　处：《物理学报》2003年第12期3155-3161,共7页Acta Physica Sinica

基　　金：河南省自然科学基金 (批准号 :0 1110 5 0 40 0 );河南省高校中青年骨干教师基金资助的课题~~

摘　　要：用第一性原理的密度泛函理论计算了PbTe(0 0 1)表面的几何结构和电子结构 .计算结果表明 :PbTe(0 0 1)表面不发生重构 ,但表面几层原子表现出明显的振荡弛豫现象 ,其中第一、第二层间距减小 4 5 % ,第二、第三层间距增加2 0 % ,并且表面层原子出现褶皱 .表面带隙在X点 ,带隙变宽 ,在基本带隙中不引入新的表面态 ,而导带底和价带顶附近等多处出现新的表面共振态 ;弛豫后费米面处态密度很低 ,所以表面结构很稳定 .The geometry and electronic structure of PbTe(001) surface are calculated using the density functional theory method. It is shown that the (001) surface has no reconstruction and exhibits a significant oscillatory geometric relaxation. The top-to-second layer distance contracts by 4.5% and the second-to-third laye r distance expands by near 2.0%. In addition, the surface shows a strong rumpli ng. The electronic structure of PbTe(001) surface differs from that of the bulk . With respect to the bulk energy gap at the L point, the surface energy gap broadens at the X point. The surface states or resonance states are localiz ed mainly near the top of the valence band and the bottom of the conduction band , while there are no new surface states appearing in the fundamental energy gap. The density of state at Fermi level of the relaxed structure of PbTe(001) surfa ce is very low, thus it is very stable.

关 键 词：密度泛函理论 表面几何结构 表面电子结构 碲化铅 第一性原理 振荡弛豫 半导体化合物 带隙结构 

分 类 号：O562[理学—原子与分子物理]