Extremely large magnetoresistance in a topological semimetal candidate pyrite PtBi2

TL;DR

This study reports extremely large, unsaturated magnetoresistance in pyrite PtBi2, a candidate topological semimetal, with experimental evidence of high mobility, quantum oscillations, and potential topological properties, surpassing known Dirac materials.

Contribution

First experimental investigation of pyrite PtBi2's magnetoresistance revealing its potential as a topological semimetal with unprecedented XMR.

Findings

Observed XMR up to 11.2 million percent at 1.8 K

Detected nontrivial Berry's phase from SdH oscillations

Hall measurements suggest electron-hole compensation

Abstract

While pyrite-type PtBi2 with face-centered cubic structure has been predicted to be a three-dimensional (3D) Dirac semimetal, experimental study on its physical properties remains absent. Here we report the angular-dependent magnetoresistance (MR) measurements of PtBi2 single-crystal under high magnetic fields. We observed extreme large unsaturated magnetoresistance (XMR) up to 11.2 million percent at T = 1.8 K in a magnetic field of 33 T, which surpasses the previously reported Dirac materials, such as WTe2, LaSb and NbP. The crystals exhibit an ultrahigh mobility and significant Shubnikov-de Hass (SdH) quantum oscillations with nontrivial Berry's phase. Analysis of Hall resistivity indicates that the XMR can be ascribed to the nearly compensated electron and hole. Our experimental results associated with the ab initio calculations suggest that pyrite PtBi2 is a topological semimetal candidate which might provide a platform for exploring topological materials with XMR in noble metal alloys.