Optically induced symmetry breaking due to nonequilibrium steady state formation in charge density wave material 1T-TiSe2

• DOI: 10.48550/arxiv.2304.13170
• Publication Date: 2023-01-01
• Authors: Harshvardhan Jog; Luminita Harnagea; Dibyata Rout; Takashi Taniguchi; Kenji Watanabe; E. J. Melé; Ritesh Agarwal
• Keywords: Charge Density Wave

The strongly correlated charge density wave (CDW) phase of 1T-TiSe$_2$ is being extensively researched to verify the claims a unique chiral order due presence three equivalent Fermi wavevectors involved in CDW formation. Characterization symmetries therefore critical understand origin their intriguing properties but can be complicated by coupling electronic and lattice degrees freedom. Here we use continuous laser excitation probe TiSe$_2$ using circular photogalvanic effect with very high sensitivity. We observe that ground state achiral. However, above threshold intensity transforms into nonequilibrium steady state, which changes correlations stacking direction layered material. inherent sensitivity technique provides clear evidence different optically driven phases 1T-TiSe$_2$, as well emphasizes interplay freedom this system under optical excitation. Our work demonstrates induced change occur at extremely low intensities materials, providing pathway for future studies engineer new light.