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打破热电材料中Wiedemann-Franz极限:通过分离的平带实现

Breaking the Wiedemann-Franz limit in thermoelectrics via separated flat bands

Illia Serhiienko, Fabian Garmroudi, Stefan Enzner, Izem Dural, Giorgio Sangiovanni, Andrej Pustogow

arXiv 2609.16261首次发表:更新:

发表机构

TU Wien; Los Alamos National Laboratory; Universität Würzburg; Laboratoire des Solides Irradiés, CEA/DRF/IRAMIS, CNRS, École Polytechnique, Institut Polytechnique de Paris(维也纳工业大学; 洛斯阿拉莫斯国家实验室; 维尔茨堡大学; 巴黎综合理工学院辐照固体实验室,法国原子能及替代能源委员会/研究与发展部/基础科学研究所,法国国家科学研究中心,巴黎理工学院)

机构由 AI 辅助整理,请以论文原文为准。

AI 中文总结

本文提出通过能量依赖散射和分离平带(如单层Ni3In)实现电子热导抑制,同时保持高电导和Seebeck系数,以打破Wiedemann-Franz极限,并利用大规模数据评估提供识别异常报告的工具。

AI 中文摘要

控制固体中电子的电荷和自旋自由度一直是凝聚态科学的核心问题,历经数百年研究。金属导电的一个标志是Wiedemann-Franz定律,它意味着移动的电荷携带熵。尽管经过数百年专门研究,将电荷输运与热输运分离至今仍未解决。在此,我们提出一种直接途径,通过能量依赖的散射来降低导电电子的热导率(相对于其电导率)。通过将电子输运限制在费米能量周围不对称的箱型分布中,可以同时实现大的Seebeck系数和电导率,同时抑制电子热传导。基于单层Ni$_3$In(其包含费米能量附近的两条平带)的案例,我们提出平带系统作为散射相空间工程的一个有前景、可调谐的平台。除了这种新方法外,我们对约$5\times 10^4$个数据集在$zT$对$S^2$的'Wiedemann-Franz图'中进行的大规模评估,提供了一种有效工具来识别文献中$L\ll L_0$的报告——这些报告要么指向新的有趣物理机制,要么指向被忽视的测量伪影。

英文摘要

Controlling the charge and spin degrees of freedom of electrons in solids has been at the heart of condensed-matter science for centuries. One hallmark of metallic conduction is the Wiedemann-Franz law which implies that a moving charge carries entropy. Despite centuries of dedicated research, disentangling charge and heat transport has remained an unsolved issue so far. Here we present a direct route to reduce thermal conductivity of conduction electrons with respect to their electrical conductivity via energy-dependent scattering. By constraining electronic transport to a boxcar-type distribution asymmetrically around the Fermi energy, a large Seebeck coefficient and electrical conductivity can be realized simultaneously while electronic heat conduction is suppressed. Based on the case of monolayer Ni$_3$In, which comprises two flat bands around the Fermi energy, we propose flat-band systems as a promising, tunable platform for scattering phase space engineering. Besides this novel approach, our large-scale assessment of $\approx 5\times 10^4$ data sets in a 'Wiedemann-Franz plot' of $zT$ vs. $S^2$ provides an effective tool to identify reports of $L\ll L_0$ from literature - pointing towards either new and interesting physical mechanisms - or overlooked measurement artifacts.

Comments8 pages, 4 figures

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