Anomalous Hall effect in Weyl semimetal half Heusler compounds RPtBi (R = Gd and Nd)

TL;DR

This study reports the observation of an unusual intrinsic anomalous Hall effect in antiferromagnetic Weyl semimetal compounds GdPtBi and NdPtBi, linked to magnetic field-induced Weyl points and topological properties.

Contribution

It provides experimental evidence of intrinsic anomalous Hall effect in Heusler Weyl semimetals GdPtBi and NdPtBi, highlighting the role of magnetic field-induced Weyl points.

Findings

GdPtBi exhibits anomalous Hall conductivity up to 60 ohm^-1cm^-1

GdPtBi shows a large anomalous Hall angle of 23%

Muon spin resonance indicates a sharp antiferromagnetic transition at 9 K

Abstract

Topological materials ranging from topological insulators to Weyl and Dirac semimetals form one of the most exciting current fields in condensed-matter research. Many half-Heusler compounds, RPtBi (R= rare earth) have been theoretically predicted to be topological semimetals. Among various topological attributes envisaged in RPtBi, topological surface states, chiral anomaly and planar Hall effect have been observed experimentally. Here, we report on an unusual intrinsic anomalous Hall effect (AHE) in the antiferromagnetic Heusler Weyl semimetal compounds GdPtBi and NdPtBi that is observed over a wide temperature range. In particular, GdPtBi exhibits an anomalous Hall conductivity of up to 60 ohm-1cm-1 and an anomalous Hall angle as large as 23%. Muon spin resonance (mu-SR) studies of GdPtBi indicate a sharp antiferromagnetic transition (T_N) at 9 K without any noticeable magnetic correlations above T_N. Our studies indicate that Weyl points in these half-Heuslers are induced by a magnetic field via exchange-splitting of the electronic bands at or near to the Fermi energy which is the source of the chiral anomaly and the AHE.