Real-time electron dynamics with exact-exchange time-dependent density-functional theory

TL;DR

This paper develops a method to accurately simulate real-time electron dynamics in quantum wells using exact-exchange time-dependent density-functional theory, highlighting the importance of memory effects near resonances.

Contribution

It introduces a numerical solution to the TDOEP integral equation for real-time electron dynamics, emphasizing the significance of memory effects over adiabatic approximations.

Findings

Memory effects are significant near intersubband resonances.

Exact exchange potential captures nonlinear electron dynamics.

Adiabatic approximations are insufficient in certain regimes.

Abstract

The exact exchange potential in time-dependent density-functional theory is defined as an orbital functional through the time-dependent optimized effective potential (TDOEP) method. We numerically solve the TDOEP integral equation for the real-time nonlinear intersubband electron dynamics in a semiconductor quantum well with two occupied subbands. By comparison with adiabatic approximations, it is found that memory effects in the exact exchange potential become significant when the electron dynamics takes place in the vicinity of intersubband resonances.