Anomalous Nernst Effect in Ferromagnetic Weyl Semimetal

TL;DR

This paper investigates the anomalous Nernst effect in ferromagnetic Weyl semimetals, demonstrating a significant conductivity driven by Berry curvature at Weyl points, using realistic lattice models of Co3Sn2S2.

Contribution

It introduces a realistic lattice Hamiltonian model for ferromagnetic Weyl semimetals, revealing the role of Berry curvature in the anomalous Nernst effect.

Findings

Large anomalous Nernst conductivity observed.

Berry curvature divergence at Weyl points drives the effect.

Realistic modeling of Co3Sn2S2 confirms theoretical predictions.

Abstract

In a three-dimensional Dirac semimetal the time reversal symmetry (TRS) or the inversion symmetry (IS) is not broken. With either of these symmetries broken, the Dirac points in the three-dimensional band structure split up into pairs of so-called Weyl points. The ferromagnetic Weyl semimetals (FMWSM), such as Co3Sn2S2, feature pairs of Weyl points characterized by the opposite chiralities. In this communication we study FMWSM based on TRS broken continuum and lattice Hamiltonians. The latter one is more realistic and represents Co3Sn2S2. These models include all essential ingredients leading to the formation of a pair of Weyl nodes and tilted Weyl cones. Our analysis shows a large anomalous Nernst conductivity which is unlocked due to the divergent Berry curvature - a local manifestation of the geometric properties of electronic wavefunctions - at Weyl points.