Time Scales of Excited State Relaxation in α-RuCl<sub>3</sub> Observed by Time-Resolved Two Photon Photoemission Spectroscopy
ORAL
Abstract
The existence of long-lived hot carriers in correlated materials is significant in the search for new quantum phasescreated by external driving and is also needed to quantify the strength and nature of complex electronic interactions. We have studied the photoexcitation dynamics in a spin-orbit assisted Mott insulator α-RuCl3 using time resolved two photon photoemission spectroscopy and differential reflection spectroscopy. We find that photoexcited carriers (doublons) in the upper Hubbard band (UHB) rapidly relax to Mott-Hubbard excitons (MHE) on a time scale of less than 200 fs. Subsequently, further fast relaxation of excitons occurs with a time constant of ~ 400 fs. After this process, the population of Mott-Hubbard excitons persists for very long times of at least several hundred picoseconds in agreement with several theoretical predictions about long-lived excited states in large gap Mott insulators.
*Surface characterization was funded by U.S. Department of Energy, Office of Science, Basic Energy Sciences under award No. DE-SC0010324. 2PPE instrumentation was funded by UNC-GA ROI Award. Theoretical modeling was supported by NSF Grant No. DMR-1752713.
–
Presenters
-
Samanvitha Sridhar
- North Carolina State University
- Physics, North Carolina State University