Warm dense matter conductivity including electron-electron collisions

TL;DR

This paper clarifies the role of electron-electron collisions in the conductivity of warm dense matter, showing their varying impact across different plasma regimes and how to incorporate them into conductivity calculations.

Contribution

It provides a comprehensive analysis of electron-electron collision effects on conductivity across plasma regimes and offers guidelines for including these effects in Kubo-Greenwood based simulations.

Findings

Electron-electron collisions reduce dc conductivity in non-degenerate plasmas.

Their impact diminishes with increasing degeneracy, becoming negligible in liquid metals.

Guidelines for implementing electron-electron collisions in conductivity calculations are provided.

Abstract

The controversy with respect to the role of electron-electron collisions in the dynamic conductivity of dense plasmas is resolved. In particular, the dc conductivity is analyzed in the low-density, non-degenerate limit where the Spitzer theory is valid and electron-electron collisions lead to the well-known reduction of the result for a Lorentz plasma. With increasing degeneracy, the contribution of electron-electron collisions to the dc conductivity is decreasing and can be neglected for the liquid metal domain where the Ziman-Faber theory is applicable. We show how electron-electron collisions have to be implemented in calculations based on the Kubo-Greenwood formula which is prevalently applied in simulations for the frequency-dependent conductivity in the warm dense matter region, i.e. for arbitrary degeneracy.