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

We 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 parameter mu*, which adds unnecessary uncertainty to T-c predictions. 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-doped beta-ZrNCl and YNi2B2C. We find that the estimated critical temperatures are consistent with those from ab-initio density functional theory for superconductors, and in close agreement with the experimental values.

Automated summary

We propose a minimal approach to incorporate static Coulomb interactions in Eliashberg theory, which can improve the prediction accuracy of superconducting properties. By simulating layered superconductors with unconventional Coulomb effects, we find that the estimated critical temperatures are consistent with experimental values and calculations from ab-initio density functional theory.