Towards a description of the Kondo effect using time-dependent density functional theory

TL;DR

This paper explores how static and time-dependent density functional theory can be used to describe the Kondo effect and conductance in the Anderson model, highlighting successes and limitations of these approaches.

Contribution

It introduces an approximate static DFT functional that captures key features of the Kondo effect and demonstrates the importance of dynamical corrections via TDDFT for accurate conductance predictions.

Findings

Exact Kohn-Sham potential at particle-hole symmetry

Correct derivative discontinuity at zero temperature

Overestimation of conductance at Kondo temperature

Abstract

We demonstrate that the zero-temperature conductance of the Anderson model can be calculated within the Landauer formalism combined with static density functional theory (DFT). The proposed approximate functional is based on finite-temperature DFT and yields the exact Kohn-Sham potential at the particle-hole symmetric point. Furthermore, in the limit of zero temperature it correctly exhibits a derivative discontinuity which is shown to be essential to reproduce the conductance plateau. On the other hand, at the Kondo temperature the exact Kohn-Sham conductance overestimates the real one by an order of magnitude. To understand the failure of DFT we resort to its time-dependent version and conclude that the suppression of the Kondo resonance with increasing temperature must be attibuted to dynamical exchange-correlation corrections.