Superconductivity in semimetals with strong Coulomb repulsion

We investigate the superconductivity of compounds with a small carrier density, such as SrTiO3, bismuth and YPtBi. In these materials, the pairing instability is often described as a consequence of charge fluctuations either due to longitudinal phonons or through the dynamic screening of the Coulomb repulsion.
Since the Fermi energy is small, the influence of interband transitions cannot be neglected in the the dynamic pairing potential. We will discuss how this alters the superconducting critical temperature in the various channels.