Shubnikov-de Haas oscillations, weak antilocalization effect and large linear magnetoresistance in the putative topological superconductor LuPdBi

TL;DR

This study investigates the electronic and magnetic properties of LuPdBi, revealing topological surface states, superconductivity, and unusual magnetoresistance behaviors, including weak antilocalization and linear magnetoresistance persisting up to room temperature.

Contribution

It provides experimental evidence of topological surface states and superconductivity in LuPdBi, a half-Heusler compound, with detailed analysis of magnetoresistance and quantum oscillations.

Findings

Observation of Shubnikov-de Haas oscillations indicating Dirac fermions.

Detection of weak antilocalization effect in magnetoresistance.

Linear, non-saturating magnetoresistance up to room temperature.

Abstract

We present electronic transport and magnetic properties of single crystals of semimetallic half-Heusler phase LuPdBi, having theoretically predicted band inversion requisite for nontrivial topological properties. The compound exhibits superconductivity below a critical temperature $T_{\rm c}=1.8\,$K, with a zero-temperature upper critical field $B_{\rm c2}\approx2.3\,$T. Although superconducting state is clearly reflected in the electrical resistivity and magnetic susceptibility data, no corresponding anomaly can be seen in the specific heat. Temperature dependence of the electrical resistivity suggests existence of two parallel conduction channels: metallic and semiconducting, with the latter making negligible contribution at low temperatures. The magnetoresistance is huge and clearly shows a weak antilocalization effect in small magnetic fields. Above about 1.5 T, the magnetoresistance becomes linear and does not saturate in fields up to 9 T. The linear magnetoresistance is observed up to room temperature. Below 10 K, it is accompanied by Shubnikov-de Haas oscillations. Their analysis reveals charge carriers with effective mass of $0.06\,m_e$ and a Berry phase very close to $\pi$, expected for Dirac-fermion surface states, thus corroborating topological nature of the material.