Thermoelectric (TE) materials are useful for applications such as waste heat harvesting or efficient and targeted cooling. While various strategies towards superior thermoelectrics through a reduction of the lattice thermal conductivity have been developed, a path to enhance the power factor is pressing. Here, we report large power factors up to 5 mW m−1 K−2 at room temperature in the kagome metal Ni3In1−xSnx. This system is predicted to feature almost dispersionless flat bands in conjunction with highly dispersive Dirac-like bands in its electronic structure around the Fermi energy EF [L. Ye et al., Nature Physics 1-5 (2024)]. Within this study, we experimentally and theoretically showcase that tuning this flat band precisely below EF by chemical doping x boosts the Seebeck coefficient and power factor, as highly mobile charge carriers scatter into the flat-band states. Our work demonstrates the prospect of engineering extremely flat and highly dispersive bands towards the Fermi energy in kagome metals and introduces topological flat bands as a novel tuning knob for thermoelectrics.
@article{arxiv.2404.08067,
title = {High thermoelectric power factor through topological flat bands},
author = {Fabian Garmroudi and Illia Serhiienko and Simone Di Cataldo and Michael Parzer and Alexander Riss and Matthias Grasser and Simon Stockinger and Sergii Khmelevskyi and Kacper Pryga and Bartlomiej Wiendlocha and Karsten Held and Takao Mori and Ernst Bauer and Andrej Pustogow},
journal= {arXiv preprint arXiv:2404.08067},
year = {2024}
}