Large Negative Magnetoresistance and Quantum Oscillation in a Field-Induced Weyl Semimetal ErAuSn

Abstract

A recent discovery of the large negative magnetoresistance (MR) effect due to chiral magnetic anomaly in topological semimetals has ignited considerable interest in these materials for both fundamental research and technological applications. However, this phenomenon requires that magnetic field must be applied along an electric current direction, which sets a severe constraint for practical applications. In this work, a large negative MR with a value of up to ≈97% is reported in an antiferromagnetic half-Heusler compound ErAuSn, which is not restricted to the crystal orientations or the specific configuration for applied magnetic fields. The combined study of high-field Shubnikov–de Haas oscillations and first-principles calculations reveals the central role of field-induced alignment of the Er moments, leading to a drastic change of the electronic band structure and a transition from the semiconducting-like phase to the Weyl semimetallic phase. The findings not only offer a guideline for searching large negative MR materials but also help to realize topological electronic states in a large class of magnetic half-Heusler compounds.