Logarithmic Criticality in Transverse Thermoelectric Conductivity of the Ferromagnetic Topological Semimetal CoMnSb

TL;DR

This study investigates the anomalous Hall and thermoelectric properties of ferromagnetic CoMnSb, revealing a unique $-T ext{ln}T$ critical behavior in thermoelectric conductivity linked to Weyl semimetal characteristics.

Contribution

It provides experimental evidence of $-T ext{ln}T$ criticality in thermoelectric conductivity and supports this with theoretical calculations near Weyl nodes.

Findings

CoMnSb exhibits sizable anomalous Hall and thermoelectric conductivities.

Thermoelectric conductivity $ ext{alpha}_{yx}$ shows $-T ext{ln}T$ behavior from 10 K to 400 K.

Theoretical models predict $-T ext{ln}T$ behavior near Weyl nodes.

Abstract

We report the results of our experimental studies on the magnetic, transport and thermoelectric properties of the ferromagnetic metal CoMnSb. Sizable anomalous Hall conductivity $\sigma_{yx}$ and transverse thermoelectric conductivity $\alpha_{yx}$ are found experimentally and comparable in size to the values estimated from density-functional theory. Our experiment further reveals that CoMnSb exhibits $-T\ln T$ critical behavior in $\alpha_{yx}(T)$, deviating from Fermi liquid behavior $\alpha_{yx}\sim T$ over a decade of temperature between 10 K to 400 K, similar to ferromagnetic Weyl and nodal-line semimetals. Our theoretical calculation for CoMnSb also predicts the $-T\ln T$ behavior when the Fermi energy locates near the Weyl nodes in momentum space.