First-principles modelling for time-resolved ARPES under different pump-probe conditions

TL;DR

This paper introduces an efficient first-principles method for time-resolved ARPES based on time-dependent density functional theory, enabling better interpretation of complex experimental data and exploration of new observables under various pump-probe conditions.

Contribution

It presents a scalable, first-principles approach for tr-ARPES that includes propagation and surface effects often neglected in other methods, applicable to diverse experimental setups.

Findings

Identified four distinct pump-probe conditions affecting ARPES signals.

Demonstrated the method's applicability to various experimental scenarios.

Enhanced understanding of time-resolved ARPES observables and their dependence on experimental parameters.

Abstract

First-principles methods for time-resolved angular resolved photoelectron spectroscopy play a pivotal role in providing interpretation and microscopic understanding of the complex experimental data and in exploring novel observables or observation conditions that may be achieved in future experiments. Here we describe an efficient, reliable and scalable first-principles method for tr-ARPES based on time-dependent density functional theory including propagation and surface effects usually discarded in the widely used many-body techniques based on computing the non-equilibrium spectral function and discuss its application to a variety of pump-probe conditions. We identify four conditions, depending on the length of the probe relative to the excitation in the materials on the one hand and on the overlap between pump and probe on the other hand. Within this paradigm different examples of observables of time-resolved ARPES are discussed in view of the newly developed and highly accurate time-resolved experimental spectroscopies.