范德瓦尔斯力
密度泛函理论
半导体
声子
电子结构
单斜晶系
热电效应
库仑
带隙
从头算
材料科学
凝聚态物理
电子能带结构
化学
晶体结构
计算化学
物理
热力学
结晶学
量子力学
光电子学
分子
电子
作者
Hexige Wuliji,Yupeng Ma,Heyang Chen,Tian‐Ran Wei,Kunpeng Zhao,Yi‐Yang Sun,Xun Shi
摘要
Silver sulfide in monoclinic phase (α-Ag2S) has attracted significant attention owing to its metal-like ductility and promising thermoelectric properties near room temperature. However, first-principles studies on this material by density functional theory calculations have been challenging as both the symmetry and atomic structure of α-Ag2S predicted from such calculations are inconsistent with experimental findings. Here, we propose that a dynamical approach is imperative for correctly describing the structure of α-Ag2S. The approach is based on a combination of ab initio molecular dynamics simulation and deliberately chosen density functional considering both proper treatment of the van der Waals interaction and on-site Coulomb interaction. The obtained lattice parameters and atomic site occupations of α-Ag2S are in good agreement with experimental data. A stable phonon spectrum at room temperature can be obtained from this structure, which also yields a bandgap in accord with experimental measurements. The dynamical approach thus paves the way for studying this important ductile semiconductor in not only thermoelectric but also optoelectronic applications.
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