Calculation of overdamped c-axis charge dynamics and the coupling to polar phonons in cuprate superconductors

TL;DR

This paper investigates how overdamped c-axis charge dynamics in cuprate superconductors influence the coupling to polar phonons, highlighting the transition from overdamped to less dissipative behavior with doping levels.

Contribution

It provides a theoretical framework explaining the evolution of c-axis charge dynamics and electron-phonon coupling across different doping regimes in cuprates.

Findings

Overdamped c-axis charge dynamics in optimally doped cuprates.

Metallic c-axis screening reduces polar electron-phonon coupling.

Less dissipation observed in overdoped cuprates.

Abstract

In our recent paper we presented empirical evidences suggesting that electrons in cuprate superconductors are strongly coupled to unscreened c-axis polar phonons. In the overdoped regime the c-axis metallizes and we present here simple theoretical arguments demonstrating that the observed effect of the metallic c-axis screening on the polar electron-phonon coupling is consistent with a strongly overdamped c-axis charge dynamics in the optimally doped system, becoming less dissipative in the overdoped regime.