Planar Hall effect in the type-II Dirac semimetal VAl3

Abstract

The study of electronic properties in topological systems is one of the most fascinating topics in condensed-matter physics, which has generated enormous interests in recent times. New materials are frequently being proposed and investigated to identify their nontrivial band structure. While sophisticated techniques such as angle-resolved photoemission spectroscopy have become popular to map the energy-momentum relation, the transport experiments lack any direct confirmation of Dirac and Weyl fermions in a system. From band-structure calculations, VAl₃ has been proposed to be a type-II topological Dirac semimetal. This material represents a large family of isostructural compounds, all having similar electronic band structure and is an ideal system to explore the rich physics of Lorentz symmetry violating Dirac fermions. In this work, we present a detailed analysis on the magnetotransport properties ofVAl₃. A large, nonsaturating magnetoresistance has been observed. Hall resistivity reveals the presence of two types of charge carriers with high mobility. Our measurements show a large planar Hall effect in this material, which is robust and can be easily detectable up to high temperature. This phenomenon originates from the relativistic chiral anomaly and nontrivial Berry curvature, which validates the theoretical prediction of the Dirac semimetal phase in VAl₃.