Topological $R$PdBi half-Heusler semimetals: a new family of non-centrosymmetric magnetic superconductors

TL;DR

This paper introduces a new family of topological semimetals, R$Pd$Bi, where tuning rare earth elements controls magnetism, superconductivity, and band topology, revealing potential for exotic quantum states.

Contribution

It reports the discovery of superconductivity and magnetism in R$Pd$Bi compounds, demonstrating tunable properties via rare earth elements and non-centrosymmetric structure, enabling exploration of topological superconductivity.

Findings

Antiferromagnetism scales with de Gennes factor.

Superconductivity is linearly suppressed with magnetic order.

Potential for spin-triplet topological superconductivity.

Abstract

We report superconductivity and magnetism in a new family of topological semimetals, the ternary half Heusler compounds $R$PdBi ($R$ : rare earth). In this series, tuning of the rare earth $f$-electron component allows for simultaneous control of both lattice density via lanthanide contraction, as well as the strength of magnetic interaction via de Gennes scaling, allowing for a unique tuning of both the normal state band inversion strength, superconducting pairing and magnetically ordered ground states. Antiferromagnetism with ordering vector (0.5,0.5,0.5) occurs below a Ne\'eel temperature that scales with de Gennes factor $dG$, while a superconducting transition is simultaneously linearly suppressed. With superconductivity appearing in a system with non-centrosymmetric crystallographic symmetry, the possibility of spin-triplet Cooper pairing with non-trivial topology analogous to that predicted for the normal state electronic structure provides a unique and rich opportunity to realize both predicted and new exotic excitations in topological materials.