Superconductivity and anomalous connection between antiferromagnetic and superconducting phases in pressurized CeRhGe₃ and related non-centrosymmetric compounds

I will 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 T_c 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 T_c^max at a common (±1.7%) critical cell volume V_crit, and T_c^max at V_crit increases with increasing spin-orbit coupling strength of the d-electrons. These correlations show that substantial Kondo hybridization/coupling and spin-orbit coupling favor superconductivity in this family, the latter reflecting the role of broken centro-symmetry. Further, anomalous connection between antiferromagnetic and superconducting phases found in pressurized CeRhGe₃ will also be presented.

The speaker would like to thank J. D. Thompson, Tao Xiang, Eric D. Bauer, Honghong Wang, Jing Guo, Yi-feng Yang, Vladimir A. Sidorov, Peijie Sun and Qi Wu for the contribution to this work.