Field‐induced quantum critical point in the pressure‐induced superconductor CeRhIn5

Abstract

AbstractWhen subjected to pressure, the prototypical heavy‐fermion antiferromagnet CeRhIn5 becomes superconducting, forming a broad dome of superconductivity (SC) centred around 2.35 GPa (=P2) with maximal Tc of 2.3 K. Above the superconducting dome, the normal state shows strange metallic behaviours, including a divergence in the specific heat and a sub‐T‐linear electrical resistivity. The discovery of a field‐induced magnetic phase that coexists with SC for a range of pressures P ≤ P2 has been interpreted as evidence for a quantum phase transition, which could explain the non‐Fermi‐liquid behaviour observed in the normal state. Here we report electrical resistivity measurements of CeRhIn5 under magnetic field at P2, where the resistivity is sub‐T‐linear for temperatures above Tc (or TFL) and a T2‐coefficient A found below TFL diverges as Hc2 is approached. These results are similar to the field‐induced quantum critical compound CeCoIn5 and confirm the presence of a quantum critical point in the pressure‐induced superconductor CeRhIn5. Temperature‐field phase diagram of CeRhIn5 at 2.35 GPa.magnified image