Quantized thermoelectric Hall plateau in the quantum limit of graphite as a nodal line semimetal

TL;DR

This study reports the observation of a quantized thermoelectric Hall plateau in graphite, confirming theoretical predictions of the thermoelectric Hall effect in nodal line semimetals and demonstrating its behavior in the quantum limit.

Contribution

First experimental observation of quantized thermoelectric Hall effect in graphite, a nodal line semimetal, validating theoretical models of thermoelectric responses in such materials.

Findings

$oldsymbol{ ext{α}}_{xy}$ forms a plateau in the quantum limit

$oldsymbol{ ext{α}}_{xy}$ shows linear temperature dependence

Experimental confirmation of thermoelectric Hall effect in nodal line semimetals

Abstract

We performed thermoelectric Hall conductivity $\alpha_{xy}$ measurements on single-crystal graphite in the quantum limit up to 13 T. Both electrical and thermoelectric transport measurements were performed on the same crystal to extract pure $\alpha_{xy}$, avoiding any sample quality dependence. The $\alpha_{xy}$ converges to a plateau in the quantum limit with a linear dependence on temperature. This behavior is analogous to the quantized thermoelectric Hall effect (QTHE) observed in three-dimensional Dirac/Weyl nodal-point semimetals, and experimentally confirms a theoretical proposal on the QTHE in semimetals with nodal lines as in graphite.