Band gap anomaly and topological properties in lead chalcogenides  

作　　者：聂思敏 许霄琰 徐刚 方忠 

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 1O0190, China [2]Collaborative Innovation Center of Quantum Matter, Beijing 100084, China

出　　处：《Chinese Physics B》2016年第3期27-34,共8页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.11204359);the National Basic Research Program of China(Grant No.2013CB921700);the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB07020100)

摘　　要：Band gap anomaly is a well-known issue in lead chalcogenides PbX （X = S, Se, Te, Po）. Combining ab initio calculations and tight-binding （TB） method, we have studied the band evolution in PbX, and found that the band gap anomaly in PbTe is mainly related to the high on-site energy of Te 5s orbital and the large s-p hopping originated from the irregular extended distribution of Te 5s electrons. Furthermore, our calculations show that PbPo is an indirect band gap （6.5 meV） semiconductor with band inversion at L point, which clearly indicates that PbPo is a topological crystalline insulator （TCI）. The calculated mirror Chern number and surface states double confirm this conclusion.Band gap anomaly is a well-known issue in lead chalcogenides PbX （X = S, Se, Te, Po）. Combining ab initio calculations and tight-binding （TB） method, we have studied the band evolution in PbX, and found that the band gap anomaly in PbTe is mainly related to the high on-site energy of Te 5s orbital and the large s-p hopping originated from the irregular extended distribution of Te 5s electrons. Furthermore, our calculations show that PbPo is an indirect band gap （6.5 meV） semiconductor with band inversion at L point, which clearly indicates that PbPo is a topological crystalline insulator （TCI）. The calculated mirror Chern number and surface states double confirm this conclusion.

关 键 词：band gap anomaly lead chalcogenides indirect band gap semiconductor topological crystallineinsulator 

分 类 号：O614.433[理学—无机化学]