Time-resolved exciton wave functions from time-dependent density-functional theory

TL;DR

This paper presents a method to extract exciton wave functions from time-dependent density-functional theory, enabling real-time analysis of exciton formation and dissociation in materials.

Contribution

The authors introduce a novel approach to obtain exciton wave functions from TDDFT using the Kohn-Sham transition density matrix, applicable in both frequency and real-time regimes.

Findings

Method provides insight into exciton dynamics in real time

Application demonstrated on one-dimensional model solids

Enables time-resolved studies of exciton behavior

Abstract

Time-dependent density-functional theory (TDDFT) is a computationally efficient first-principles approach for calculating optical spectra in insulators and semiconductors, including excitonic effects. We show how exciton wave functions can be obtained from TDDFT via the Kohn-Sham transition density matrix, both in the frequency-dependent linear-response regime and in real-time propagation. The method is illustrated using one-dimensional model solids. In particular, we show that our approach provides insight into the formation and dissociation of excitons in real time. This opens the door to time-resolved studies of exciton dynamics in materials by means of real-time TDDFT.