# Berry curvature unravelled by the Nernst effect in Mn$_3$Ge

## TL;DR

This paper demonstrates that the Nernst effect can be used to probe Berry curvature and Weyl physics in Mn$_3$Ge, revealing key parameters of Weyl points through thermoelectric measurements.

## Contribution

It introduces the Nernst effect as a novel, sensitive method to determine Weyl point parameters in topological semimetals, specifically applied to Mn$_3$Ge.

## Key findings

- Direct measurement of Berry curvature at the Fermi level
- Extraction of Weyl point energy and momentum-space distance
- Identification of anomalous thermoelectric transport due to Weyl points

## Abstract

The discovery of topological quantum materials represents a striking innovation in modern condensed matter physics with remarkable fundamental and technological implications. Their classification has been recently extended to topological Weyl semimetals, i.e., solid state systems which exhibit the elusive Weyl fermions as low-energy excitations. Here we show that the Nernst effect can be exploited as a sensitive probe for determining key parameters of the Weyl physics, applying it to the non-collinear antiferromagnet Mn$_3$Ge. This compound exhibits anomalous thermoelectric transport due to enhanced Berry curvature from Weyl points located extremely close to the Fermi level. We establish from our data a direct measure of the Berry curvature at the Fermi level and, using a minimal model of a Weyl semimetal, extract for the first time the Weyl point energy and their distance in momentum-space.