Multiple Superconducting Phases in New Heavy Fermion Superconductor PrOs4Sb12

TL;DR

This study reveals multiple superconducting phases in PrOs4Sb12, characterized by distinct gap symmetries and point node singularities, indicating complex pairing mechanisms in this heavy fermion superconductor.

Contribution

It uncovers the existence of two distinct superconducting phases with different symmetries and gap structures in PrOs4Sb12, a novel finding in heavy fermion superconductors.

Findings

Identification of two superconducting phases with twofold and fourfold symmetries.

Discovery of point node singularities in both phases.

Evidence of a symmetry change deep inside the superconducting state.

Abstract

The superconducting gap structure of recently discovered heavy fermion superconductor PrOs4Sb12 was investigated by using thermal transport measurements in magnetic field rotated relative to the crystal axes. We demonstrate that a novel change in the symmetry of the superconducting gap function occurs deep inside the superconducting state, giving a clear indication of the presence of two distinct superconducting phases with twofold and fourfold symmetries. We infer that the gap functions in both phases have a point node singularity, in contrast to the familiar line node singularity observed in almost all unconventional superconductors.