Magnetic and superconducting phase diagram of the half-Heusler topological semimetal HoPdBi

TL;DR

This study explores the magnetic, electronic, and topological properties of HoPdBi, revealing its semimetallic behavior, antiferromagnetic order, bulk superconductivity, and classification as a new topological semimetal with a non-trivial band inversion.

Contribution

It provides the first comprehensive phase diagram of HoPdBi, combining experimental and theoretical insights into its magnetic, superconducting, and topological characteristics.

Findings

HoPdBi exhibits semimetallic behavior with low carrier concentration.

Superconductivity occurs below 1.9 K within the antiferromagnetic phase.

Electronic structure calculations classify HoPdBi as a topological semimetal with band inversion.

Abstract

We report a study of the magnetic and electronic properties of the non-centrosymmetric half-Heusler antiferromagnet HoPdBi ($T_N = 2.0$ K). Magnetotransport measurements show HoPdBi has a semimetallic behaviour with a carrier concentration $n=3.7 \times 10^{18}$ cm$^{-3}$ extracted from the Shubnikov-de Haas effect. The magnetic phase diagram in the field-temperature plane has been determined by transport, magnetization and thermal expansion measurements: magnetic order is suppressed at $B_M\sim 3.6$ T for $T \rightarrow 0$. Superconductivity with $T_c \sim 1.9$ K is found in the antiferromagnetic phase. Ac-susceptibility measurements provide solid evidence for bulk superconductivity below $T_c = 0.75$ K with a screening signal close to a volume fraction of 100 %. The upper critical field shows an unusual linear temperature variation with $B_{c2}(T \rightarrow 0) = 1.1$ T. We also report electronic structure calculations that classify HoPdBi as a new topological semimetal, with a non-trivial band inversion of 0.25 eV.