Unconventional superconductivity and antiferromagnetic quantum phase transition in [formula omitted]: 115In-NQR study under pressure

Abstract

We report on the pressure ( P)-induced phase diagram of antiferromagnetism (AFM) and superconductivity (SC) which emerges at their border at zero magnetic field. The nuclear-quadrupole-resonance (NQR) measurements have revealed that AFM can take place in the superconducting state with T c ∼ 2.1 K at P = 2.05 GPa and the AFM quantum phase transition (QPT) occurs near P = 2.1 GPa . These results reveal the existence of the tetracritical point in the P– T phase diagram of AFM and SC in CeRnIn 5 . We also found the gapless nature in the uniformly coexisting phase of AFM and SC, indicating an intimate relationship between AFM and SC.