First‐principles calculations, within the framework of density functional theory, are used to investigate the structural, electronic, optical, and thermoelectric properties of monolayer PbTe. The effect of layer thickness, electric field, strain, and vacancy defects on the electronic and magnetic properties is systematically studied. The results show that the bandgap decreases as the layer thickness increases from monolayer to bulk. With application of an electric field on bilayer PbTe, the bandgap decreases from 70 meV (0.2 V Å⁻¹) to 50 meV (1 V Å⁻¹) when including spin–orbit coupling (SOC). Application of uniaxial strain induces a direct‐to‐indirect bandgap transition for strain greater than +6%. In addition, the bandgap decreases under compressive biaxial strain (with SOC). The effect of vacancy defects on the electronic properties of PbTe is also investigated. Such vacancy defects turn PbTe into a ferromagnetic metal (single vacancy Pb) with a magnetic moment of 1.3 μ _B, and into an indirect semiconductor with bandgap of 1.2 eV (single Te vacancy) and 1.5 eV (double Pb + Te vacancy). In addition, with change of the Te vacancy concentration, a bandgap of 0.38 eV (5.55%), 0.43 eV (8.33%), and 0.46 eV (11.11%) is predicted.

中文翻译：

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单层PbTe的电子，光学和热电性质以及通过外场和缺陷对电子结构的可调性

在密度泛函理论框架内的第一性原理计算用于研究单层PbTe的结构，电子，光学和热电性质。系统地研究了层厚度，电场，应变和空位缺陷对电子和磁性的影响。结果表明，带隙随着层厚度从单层增加到整体而减小。在双层PbTe上施加电场后，带隙从70 meV（0.2 VÅ ^-1）降至50 meV（1 VÅ ^-1），包括自旋轨道耦合（SOC）。单轴应变的应用会导致应变大于+ 6％的直接到间接的带隙跃迁。此外，带隙在压缩双轴应变（带有SOC）下减小。还研究了空位缺陷对PbTe电子性能的影响。例如空位缺陷转的PbTe与1.3的磁矩的铁磁性金属（单空位Pb）的 μ_乙，并与1.2电子伏特（单碲空位）和1.5电子伏特（双铅+碲空缺）的带隙的半导体间接。另外，随着Te空位浓度的变化，预测带隙为0.38eV（5.55％），0.43eV（8.33％）和0.46eV（11.11％）。