# Electron-phonon coupling and pairing mechanism in $\beta$--Bi$_2$Pd centrosymmetric superconductor

## TL;DR

This paper uses first-principles calculations to analyze the electron-phonon interactions and superconducting properties of $eta$--Bi$_2$Pd, revealing an anisotropic s-wave gap consistent with experimental data.

## Contribution

It provides a detailed theoretical analysis of the pairing mechanism in $eta$--Bi$_2$Pd using the Migdal-Eliashberg formalism, confirming phonon-mediated superconductivity with an anisotropic gap.

## Key findings

- Superconducting gap is anisotropic s-wave on the Fermi surface.
- Calculated properties agree with experimental measurements.
- Supports phonon-mediated pairing mechanism in $eta$--Bi$_2$Pd.

## Abstract

We report first-principles calculations of the superconducting properties of $\beta$--Bi$_2$Pd within the fully anisotropic Migdal-Eliashberg formalism. We find a single anisotropic superconducting gap of $s$--wave symmetry which varies in magnitude on the different regions of the Fermi surface. The calculated superconducting energy gap on the Fermi surface, the superconducting transition temperature, the specific heat, and the quasi-particle density of states are in good agreement with the corresponding experimental results and support the view that $\beta$--Bi$_2$Pd is a phonon-mediated single anisotropic gap superconductor.