Fully gapped superconductivity with no sign change in the prototypical heavy-fermion CeCu₂Si₂.

ABSTRACT: In exotic superconductors, including high-T_c copper oxides, the interactions mediating electron Cooper pairing are widely considered to have a magnetic rather than a conventional electron-phonon origin. Interest in this exotic pairing was initiated by the 1979 discovery of heavy-fermion superconductivity in CeCu₂Si₂, which exhibits strong antiferromagnetic fluctuations. A hallmark of unconventional pairing by anisotropic repulsive interactions is that the superconducting energy gap changes sign as a function of the electron momentum, often leading to nodes where the gap goes to zero. We report low-temperature specific heat, thermal conductivity, and magnetic penetration depth measurements in CeCu₂Si₂, demonstrating the absence o

SUBMITTER: Yamashita T 

PROVIDER: S-EPMC5482556 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature