标题： 掺杂反位缺陷对Fe_2VAl塞贝克系数的影响 -- 基于双极随机安德森模型的分析 显示英文标题

标题： Effects of Antisite Defects on Seebeck Coefficient in Fe_2VAl -- Analyses based on Bipolar Random Anderson Model

摘要： 一种微观机制被提出，用于解释在Fe$_2$VAl中引入反位缺陷后塞贝克系数从正号到负号的显著符号变化，该机制基于双极随机安德森模型（BPRAM），该模型结合了随机分布的反位缺陷与基质带之间的杂化效应，由于价带和导带在动量空间中的分离，因此分别处理这两个带。 应用自洽T矩阵近似，我们发现Fe$_2$VAl中的反位缺陷在带重叠区域诱导出新的状态，导致价带中的空穴载流子的散射率高于导带中的电子载流子，从而导致负的塞贝克系数。 这种符号变化机制为在不改变载流子浓度的情况下控制半金属系统中的热电性能提供了一种潜在的新方法。 显示英文摘要

摘要： A microscopic mechanism is proposed for a dramatic sign change of the Seebeck coefficient from positive to negative sign by the introduction of antisite defects in Fe$_2$VAl based on bipolar random Anderson model (BPRAM), which incorporates hybridization effects between randomly distributed antisites and host bands, where the valence and conduction bands are treated separately due to their separation in momentum space. Applying a self-consistent T-matrix approximation, we find that antisite defects in Fe$_2$VAl induce new states in the band overlap region, resulting in a scattering rate that is higher for hole carriers in the valence band than that for electron carriers in the conduction band, leading to negative Seebeck coefficient. This mechanism of sign change presents a potential new approach for controlling thermoelectric properties in semimetallic systems without changing carrier concentration.