Abstract
is an excitonic insulator candidate showing the semiconductor or semimetal-to-insulator (SI) transition below . However, since a structural transition accompanies the SI transition, deciphering the role of electronic and lattice degrees of freedom in driving the SI transition has remained controversial. Here, we investigate the photoexcited nonequilibrium state in using pump-probe Raman and photoluminescence spectroscopies. The combined nonequilibrium spectroscopic measurements of the lattice and electronic states reveal the presence of a photoexcited metastable state where the insulating gap is suppressed, but the low-temperature structural distortion is preserved. We conclude that electron correlations play a vital role in the SI transition of .
- Received 15 November 2022
- Accepted 14 February 2023
DOI:https://doi.org/10.1103/PhysRevLett.130.106904
© 2023 American Physical Society