Hg3In2Te6(简称MIT)是Ⅱ-Ⅵ/Ⅲ-Ⅵ族化合物半导体Hg(3-3x)In2xTe3中x=0.5时对应的稳定相。本文采用第一性原理方法, 系统地探究了Au在MIT中的稳定性和掺杂效率。计算结果表明: Au-Te键具有与Hg-Te相似的极性共价键特性, 表明Au在MIT中具有一定掺杂稳定性。此外, 发现Au在MIT中存在两性掺杂特性: Au在AuHg和AuIn体系中表现受主特性, Au-5d电子轨道分别在价带顶和-4 eV位置与Te-5p电子轨道形成共振, 形成受主杂质能级; 而Au在AuTe和AuI体系中表现施主特性, Au-5d与Hg-6s、In-5s电子轨道在导带底产生共振, 形成施主杂质能级。富Hg条件下, AuI、AuTe与AuHg之间会产生自我补偿效应, 费米能级被钉扎在价带顶, 而富Te条件下, 上述自我补偿效应将会得到有效消除。

Hg3In2Te6 (MIT for short) is a stable phase corresponding to x=0.5 in the Ⅱ-Ⅵ/Ⅲ-Ⅵ compound semiconductor Hg(3-3x)In2xTe3. In this paper, the stability and doping efficiency of Au in MIT were systematically investigated using the first-principles method. The results show that Au-Te bonds has polar covalent bond characteristics similar to that of Hg-Te bonds in MIT, indicating that Au has certain doping stability in MIT. In addition, it is found that there are amphoteric doping properties of Au in MIT: Au exhibits acceptor properties in AuHg and AuIn systems, and the Au-5d electron orbital resonates with the Te-5p electron orbital at the top of the valence band and -4 eV position, respectively, forming acceptor defect levels. While Au exhibits donor characteristics in AuTe and AuI systems, Au-5d resonates with Hg-6s and In-5s electron orbitals at the conduction band bottom, forming donor defect levels. It is worth noting that under Hg-rich conditions, there will be a self-compensation effect between AuI, AuTe and AuHg systems, and the Fermi level will be pinned at the top of valence band, while under Te-rich conditions, the self-compensation effect will be effectively eliminated.