Topological charge-entropy scaling in kagome Chern magnet TbMn$_6$Sn$_6$

TL;DR

This paper demonstrates topological charge-entropy scaling in the kagome Chern magnet TbMn$_6$Sn$_6$, revealing Dirac fermions and Berry curvature effects through electric and thermoelectric transport measurements, with implications for topological quantum materials.

Contribution

It provides the first experimental observation of charge-entropy scaling relations governed by Berry curvature in a kagome Chern magnet, supported by transport data and a Dirac model.

Findings

Observation of quantum oscillations with nontrivial Berry phase

Large anomalous Hall, Nernst, and thermal Hall effects above room temperature

Charge-entropy relations described by Berry curvature in a Dirac model

Abstract

In ordinary materials, electrons conduct both electricity and heat, where their charge-entropy relations observe the Mott formula and the Wiedemann-Franz law. In topological quantum materials, the transverse motion of relativistic electrons can be strongly affected by the quantum field arising around the topological fermions, where a simple model description of their charge-entropy relations remains elusive. Here we report the topological charge-entropy scaling in the kagome Chern magnet TbMn$_6$Sn$_6$, featuring pristine Mn kagome lattices with strong out-of-plane magnetization. Through both electric and thermoelectric transports, we observe quantum oscillations with a nontrivial Berry phase, a large Fermi velocity and two-dimensionality, supporting the existence of Dirac fermions in the magnetic kagome lattice. This quantum magnet further exhibits large anomalous Hall, anomalous Nernst, and anomalous thermal Hall effects, all of which persist to above room temperature. Remarkably, we show that the charge-entropy scaling relations of these anomalous transverse transports can be ubiquitously described by the Berry curvature field effects in a Chern-gapped Dirac model. Our work points to a model kagome Chern magnet for the proof-of-principle elaboration of the topological charge-entropy scaling.