Eliashberg theory with ab-initio Coulomb interactions: a minimal numerical scheme applied to layered superconductors

Abstract

AbstractWe present a minimal approach to include static Coulomb interactions in Eliashberg theory of superconductivity from first principles. The method can be easily implemented in any existing Eliashberg code (isotropic or anisotropic) to avoid the standard use of the semiempirical parameterμ∗, which adds unnecessary uncertainty toTcpredictions. We evaluate the prediction accuracy of the method by simulating the superconducting properties of a set of layered superconductors, which feature unconventional Coulomb effects: CaC6, MgB2, Li-dopedβ-ZrNCl and YNi2B2C. We find that the estimated critical temperatures are consistent with those fromab-initiodensity functional theory for superconductors, and in close agreement with the experimental values.