Time-resolved photoemission of correlated electrons driven out of equilibrium

TL;DR

This paper investigates the real-time evolution of photoemission in a correlated electron system driven out of equilibrium, revealing complex dynamics and spectral weight redistribution near a metal-insulator transition using an exact theoretical approach.

Contribution

It provides an exact time-domain solution for the Falicov-Kimball model's nonequilibrium dynamics, highlighting differences from common simplified models and emphasizing the impact of probe pulse width.

Findings

Reveals spectral weight redistribution during nonequilibrium evolution.

Shows differences from hot electron and quench models.

Highlights the trade-off between energy and time resolution.

Abstract

We describe the temporal evolution of the time-resolved photoemission response of the spinless Falicov-Kimball model driven out of equilibrium by strong applied fields. The model is one of the few possessing a metal-insulator transition and admitting an exact solution in the time domain. The nonequilibrium dynamics, evaluated using an extension of dynamical mean-field theory, show how the driven system differs from two common viewpoints - a quasiequilibrium system at an elevated effective temperature (the "hot" electron model) or a rapid interaction quench ("melting" of the Mott gap) - due to the rearrangement of electronic states and redistribution of spectral weight. The results demonstrate the inherent trade-off between energy and time resolution accompanying the finite width probe pulses, characteristic of those employed in pump-probe time-domain experiments, which can be used to focus attention on different aspects of the dynamics near the transition.