Abstract
Specific heat has been investigated in a layered nitride superconductor, , with . The obtained data have shown a marked dichotomy: The specific heat jump at () and the superconducting gap ratio () have indicated an intermediate to a strong coupling of electrons, while the upper limit of the electron-phonon coupling constant has directly been estimated to be 0.22, which belongs to a weak coupling regime. Furthermore, the rapid increase of as a function of magnetic field suggests that the present material has an anisotropic wave gap.
- Received 26 January 2005
DOI:https://doi.org/10.1103/PhysRevLett.94.217002
©2005 American Physical Society