Anomalous and parallel Hall effects in ferromagnetic Weyl semimetal Cr$_3$Te$_4$

TL;DR

This paper predicts and experimentally investigates the anomalous and parallel Hall effects in ferromagnetic Weyl semimetal Cr$_3$Te$_4$, revealing robust Weyl points, surface states, and significant Berry curvature effects near the Fermi level.

Contribution

It introduces the first theoretical prediction of multiple Weyl points and associated Hall effects in Cr$_3$Te$_4$, supported by experimental validation of magnetic properties.

Findings

Presence of multiple Weyl points near the Fermi level

Large, robust Fermi arcs and surface states

Significant anomalous Hall and Nernst conductivities

Abstract

Recently, time-reversal symmetry broken magnetic Weyl semimetals (WSMs) have attracted extensive attention and have provided an intriguing platform for exploring fundamental physical phenomena. The study of chromium telluride-based systems has also drawn significant interest towards spintronics applications owing to their high Curie temperatures. Here, using \textit{ab initio} calculations, we propose the emergence of multiple Weyl points (WPs) near the Fermi level in such an intrinsic ferromagnetic system, Cr$_3$Te$_4$. The large, well-separated, nontrivial Fermi arcs and surface states, suggest that the WPs are highly robust and resilient to perturbations. A substantial Berry curvature contribution in the vicinity of the Fermi energy not only serves as the origin of large conventional anomalous Hall conductivity (AHC), but also produces unconventional parallel AHC in this material, owing to the low structural symmetry. In addition to the charge Hall conductivity, we also find significant anomalous Nernst conductivities originating from the Berry curvature. Alongside our theoretical predictions, we present complementary experimental results, including X-ray diffraction (XRD) analysis and an examination of the magnetic properties, which demonstrate a Curie temperature of 327 K. Our study advances the understanding of magnetic WSMs, and also encourages further studies in the context of topological properties of our proposed material.