Giant anomalous thermal Hall effect in tilted type-I magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$

TL;DR

This study reveals a giant anomalous thermal Hall effect in the magnetic Weyl semimetal Co3Sn2S2, showing large Berry curvature-induced signals, sign-reversal behavior, and stress-enhanced conductivity, with implications for experimental detection.

Contribution

It provides the first detailed theoretical analysis of the anomalous thermal Hall effect in Co3Sn2S2, highlighting its giant magnitude and tunability via strain and chemical potential.

Findings

Giant anomalous thermal Hall signal due to Berry curvature.

Sign-reversal of thermal Hall current with chemical potential.

Stress enhances conductivity by up to 33%."

Abstract

The recent discovery of magnetic Weyl semimetal Co3Sn2S2 opens up new avenues for research into the interactions between topological orders, magnetism, and electronic correlations. Motivated by the observations of large anomalous Hall effect because of large Berry curvature, we investigate another Berry curvature-induced phenomenon, the anomalous thermal Hall effect in Co3Sn2S2. We study it with and without strain, using a Wannier tight-binding Hamiltonian derived from first principles density functional theory calculations. We first identify this material as a tilted type-I Weyl semimetal based on the band structure calculation. Within the quasi-classical framework of Boltzmann transport theory, a giant anomalous thermal Hall signal appears due to the presence of large Berry curvature. Surprisingly, the thermal Hall current changes and even undergoes a sign-reversal upon varying the chemical potential. Furthermore, applying about 13 GPa stress, an enhancement as large as 33% in the conductivity is observed; however, the tilt vanishes along the path connecting the Weyl nodes. In addition, we have confirmed the validity of the Wiedemann-Franz law in this system for anomalous transports. We propose specific observable signatures that can be directly tested in experiments.