Theoretical description of time-resolved photoemission spectroscopy: application to pump-probe experiments

TL;DR

This paper develops a comprehensive theoretical framework for time-resolved photoemission spectroscopy in pump-probe experiments, accounting for nonequilibrium effects and finite pulse widths, with numerical insights into strongly correlated materials.

Contribution

It provides a general formalism for modeling time-resolved photoemission, including effects of pump pulses and probe windowing, applied specifically to the Hubbard model.

Findings

Sharp spectral features are broadened due to finite probe width.

The quasiparticle peak in strongly correlated metals is affected by broadening.

The theory captures nonequilibrium dynamics during pump-probe experiments.

Abstract

The theory for time-resolved photoemission spectroscopy as applied to pump-probe experiments is developed and solved for the generic case of a strongly correlated material. The formal development incorporates all of the nonequilibrium effects of the pump pulse and the finite time width of the probe pulse. While our formal development is completely general, in our numerical illustration for the Hubbard model, we assume the pump pulse drives the electrons into a nonequilibrium configuration, which rapidly thermalizes to create a hot (quasi-equilibrium) electronic system, and we then study the effects of windowing that arise from the finite width of the probe pulse. We find sharp features in the spectra are broadened, particularly the quasiparticle peak of strongly correlated metals at low temperature.