Superconductivity in pressurized CeRhGe3 and related non-centrosymmetric compounds

TL;DR

This paper reports the discovery of pressure-induced superconductivity in CeRhGe3, a non-centrosymmetric heavy-fermion compound, and explores systematic correlations between superconductivity, spin-orbit coupling, and material properties within its family.

Contribution

It is the first to demonstrate superconductivity in CeRhGe3 under pressure and links superconducting properties to spin-orbit coupling and Kondo hybridization across the CeTX3 family.

Findings

Superconductivity in CeRhGe3 appears at 19.6 GPa with Tc up to 1.3 K.

Maximum Tc occurs at a common critical cell volume across the family.

Higher spin-orbit coupling correlates with increased maximum Tc.

Abstract

We report the discovery of superconductivity in pressurized CeRhGe3, until now the only remaining non-superconducting member of the isostructural family of non-centrosymmetric heavy-fermion compounds CeTX3 (T = Co, Rh, Ir and X = Si, Ge). Superconductivity appears in CeRhGe3 at a pressure of 19.6 GPa and the transition temperature Tc reaches a maximum value of 1.3 K at 21.5 GPa. This finding provides an opportunity to establish systematic correlations between superconductivity and materials properties within this family. Though ambient-pressure unit-cell volumes and critical pressures for superconductivity vary substantially across the series, all family members reach a maximum Tcmax at a common critical cell volume Vcrit, and Tcmax at Vcrit increases with increasing spin-orbit coupling strength of the d-electrons. These correlations show that substantial Kondo hybridization and spin-orbit coupling favor superconductivity in this family, the latter reflecting the role of broken centro-symmetry.