Forward Electron-Phonon Scattering in Normal and Superconducting States

TL;DR

This paper investigates how sharp forward electron-phonon and impurity scattering influence the properties of normal and superconducting states, revealing effects like pseudo-gap features and linear T_c dependence on coupling.

Contribution

It introduces the impact of forward scattering processes on superconductivity and impurity effects, highlighting their significance in modifying electronic properties.

Findings

Pseudo-gap features appear in the density of states for energies below phonon frequency.

Superconducting T_c scales linearly with electron-phonon coupling due to forward scattering.

Impurities weaken pairing in s- and d-wave superconductors.

Abstract

The sharp forward electron-phonon $(FEP)$ and impurity $(FIS)$ scattering change the normal and superconducting properties significantly. The pseudo-gap like features are present in the density of states for $\omega <\Omega $, where $\Omega $ is the phonon frequency. The superconducting critical temperature $T_c$, due to the $FEP$ pairing, is linear with respect to the electron-phonon coupling constant. The $FIS$ impurities are pair weakening for $s-$ and $d-wave$ pairing.