Current-dependent exchange-correlation potential for dynamical linear response theory

TL;DR

This paper introduces a current-dependent exchange-correlation potential within a generalized Kohn-Sham framework, enabling local approximations for frequency-dependent response calculations in density functional theory.

Contribution

It proposes a new approach using current-density as the basic variable to achieve local approximations in time-dependent response theory.

Findings

The current-dependent potential is exact for slowly varying densities at fixed frequency.

The approach circumvents the nonlocality problem of traditional exchange-correlation potentials.

It provides a practical way to improve local density approximations in dynamical response calculations.

Abstract

The frequency-dependent exchange-correlation potential, which appears in the usual Kohn-Sham formulation of a time-dependent linear response problem, is a strongly nonlocal functional of the density, so that a consistent local density approximation generally does not exist. This problem can be avoided by choosing the current-density as the basic variable in a generalized Kohn-Sham theory. This theory admits a local approximation which, for fixed frequency, is exact in the limit of slowly varying densities and perturbing potentials.