Photoinduced charge dynamics in 1T-TaS2

Recent theoretical studies showed that the electronic structure of 1T-TaS2 in the low-temperature commensurate charge density wave phase exhibits a nontrivial interplay between band-insulating and Mott-insulating behavior. This has important implications for the interpretation of photodoping experiments. Here we use nonequilibrium dynamical mean-field theory simulations of a realistic multilayer structure to clarify the charge carrier dynamics induced by a laser pulse. The solution is propagated up to the picosecond timescale by employing a memory-truncation scheme. While long-lived doublons and holons only exist in the surface state of a specific structure, the disturbance of bonding states in the bilayers which make up the bulk of the system explain the almost instantaneous appearance of in-gap states. Our simulations consistently explain the coexistence of a doublon feature with a prominent background signal in previous time-resolved photoemission experiments, and they suggest strategies for the selective population of the in-gap and doublon states by exploiting the sensitivity to the pump polarization and pump frequency.

Automated summary

Recent theoretical studies reveal the interplay between band-insulating and Mott-insulating behavior in the low-temperature commensurate charge density wave phase of 1T-TaS2, which has important implications for photodoping experiments. In this study, nonequilibrium dynamical mean-field theory simulations are used to investigate the charge carrier dynamics induced by a laser pulse in a realistic multilayer structure. The simulations provide insight into the appearance of in-gap states and explain the coexistence of doublon features with a background signal in previous time-resolved photoemission experiments.