Treatment of electron viscosity in quantum conductance

TL;DR

This paper revises the calculation of dynamical exchange-correlation resistance in quantum conductance by proposing a more accurate form for electron viscosity, significantly reducing estimated resistance corrections.

Contribution

It introduces an improved model for shear electron viscosity, leading to more accurate estimations of dynamical resistance in nanoscale quantum conductance.

Findings

Revised electron viscosity reduces dynamical resistance estimates

More accurate viscosity models improve quantum conductance calculations

Significant impact on interpretation of nanoscale transport phenomena

Abstract

In a recent paper Sai {\it et al.} [1] identified a correction $R^{dyn}$ to the DC conductance of nanoscale junctions arising from dynamical exchange-correlation ($XC$) effects within time-dependent density functional theory. This quantity contributes to the total resistance through $R=R_{s}+R^{dyn}$ where $R_{s}$ is the resistance evaluated in the absence of dynamical $XC$ effects. In this Comment we show that the numerical estimation of $R^{dyn}$ in example systems of the type they considered should be considerably reduced, once a more appropriate form for the shear electron viscosity $\eta$ is used.