SnTe中Zn杂质的双重特性：调控热电与拓扑性质
On the dual character of Zn impurity in SnTe: Tuning thermoelectric and topological properties
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中文总结 AI 辅助
该研究通过第一性原理计算揭示Zn掺杂SnTe中Zn的双重作用：在导带形成类共振态增强n型热电性能，在价带诱导带收敛提升p型性能，并驱动拓扑相变，实现热电与拓扑性质的协同调控。
中文摘要 AI 辅助
我们利用相干势近似下的Korringa-Kohn-Rostoker方法，并辅以赝势计算，对Zn掺杂SnTe的电子结构和热电性质进行了第一性原理研究。SnTe是PbTe的无铅类似物，也是一种候选热电材料，实验已报道Zn掺杂可提升p型样品的性能。我们表明，Zn在导带内引入一个类共振杂质态，该态随Zn浓度的变化而显著演化。这一特征导致n型SnTe的热电势显著增强。在价带中，Zn掺杂诱导L-Σ带收敛，从而在较宽的浓度范围内提高p型Seebeck系数，并延迟双极效应的 onset。我们进一步证明，Zn引起的能带结构修饰驱动了从反转能带序到平凡能带序的转变，表明存在可控的拓扑相变。我们的结果阐明了Zn在SnTe中的微观作用，并指出掺杂是同时调控热电和拓扑性质的一种机制。
英文摘要
We present a first-principles study of the electronic structure and thermoelectric properties of Zn-doped SnTe using the Korringa-Kohn-Rostoker method within the coherent potential approximation, complemented by pseudopotential calculations. SnTe is a lead-free analogue of PbTe and a candidate thermoelectric material in which Zn doping has been experimentally reported to enhance the performance of $p$-type samples. We show that Zn introduces a resonant-like impurity state, located within the conduction band, which evolves strongly depending on the Zn concentration. This feature leads to a significant enhancement of the thermopower in $n$-type SnTe. In the valence band, Zn doping induces L-$Σ$ band convergence, also resulting in an increased $p$-type Seebeck coefficient over a broad concentration range and delaying the onset of the bipolar effect. We further demonstrate that the Zn-induced band-structure modifications drive a transition from an inverted to a trivial band ordering, indicating a controllable topological phase transition. Our results clarify the microscopic role of Zn in SnTe and identify doping as a mechanism for simultaneously tuning thermoelectric and topological properties.
发表机构
- AGH University of Krakow, Faculty of Physics and Applied Computer Science（克拉科夫AGH科技大学物理与应用计算机科学学院）
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