# Anomalous thermoelectric effects of ZrTe$_{5}$ in and beyond the quantum limit

## TL;DR

This paper investigates the unusual thermoelectric effects in ZrTe$_{5}$ under magnetic fields, revealing anomalous behaviors linked to topological properties and Landau level dynamics, advancing understanding of Dirac physics in topological materials.

## Contribution

It uncovers novel anomalous thermoelectric phenomena in ZrTe$_{5}$ related to Berry curvature and Landau level inversion, providing new insights into Dirac physics in topological materials.

## Key findings

- Steplike Nernst response near zero field due to Berry curvature
- Exotic peaks in thermopower and Nernst signal in the quantum limit
- Sign reversal of Nernst signal at high magnetic fields

## Abstract

Thermoelectric effects are more sensitive and promising probes to topological properties of emergent materials, but much less addressed compared to other physical properties. Zirconium pentatelluride (ZrTe$_{5}$) has inspired active investigations recently because of its multiple topological nature. We study the thermoelectric effects of ZrTe$_{5}$ in a magnetic field and find several anomalous behaviors. The Nernst response has a steplike profile near zero field when the charge carriers are electrons only, suggesting the anomalous Nernst effect arising from a nontrivial profile of Berry curvature. Both the thermopower and Nernst signal exhibit exotic peaks in the strong-field quantum limit. At higher magnetic fields, the Nernst signal has a sign reversal at a critical field where the thermopower approaches to zero. We propose that these anomalous behaviors can be attributed to the Landau index inversion, which is resulted from the competition of the $\sqrt{B}$ dependence of the Dirac-type Landau bands and linear-$B$ dependence of the Zeeman energy ($B$ is the magnetic field). Our understanding to the anomalous thermoelectric properties in ZrTe$_{5}$ opens a new avenue for exploring Dirac physics in topological materials.