Lead chalcogenides are known for their thermoelectric properties since the first work of Thomas Seebeck on the discovery of this phenomenon. Yet, the electronic properties of lead telluride are still of interest due to the incomplete understanding of the metal-to-semiconductor transition at temperatures around 230 °C. Here, a temperature-dependent atomic-resolution transmission electron microscopy study performed on a single crystal of lead telluride reveals structural reasons for this electronic transition. Below the transition temperature, the formation of a dislocation network due to shifts of the NaCl-like atomic slabs perpendicular to {100} was observed. The local structure modification leads to the appearance of in-gap electronic states and causes metal-like electronic transport behavior. The dislocation network disappears with increasing temperature, yielding semiconductor-like electrical conductivity, and re-appears after cooling to room temperature restoring the metal-like behavior. The structural defects coupled to the ordering of stereochemically active lone pairs of lead atoms are discussed in the context of dislocations' formation.

自从 Thomas Seebeck 首次发现这种现象以来，硫属元素铅就以其热电特性而闻名。然而，由于对 230°C 左右温度下金属到半导体的转变的不完全了解，碲化铅的电子特性仍然令人感兴趣。在这里，对碲化铅单晶进行的温度相关原子分辨率透射电子显微镜研究揭示了这种电子跃迁的结构原因。在转变温度以下，观察到由于类 NaCl 原子板垂直于 {100} 的位移而形成的位错网络。局部结构改变导致间隙内电子态的出现并导致类似金属的电子传输行为。位错网络随着温度的升高而消失，产生类似半导体的导电性，并在冷却至室温后重新出现，恢复类似金属的行为。在位错形成的背景下讨论了与立体化学活性孤对铅原子的排序相关的结构缺陷。