Revealing Light-Induced Charge Density Wave Melting and Carrier Redistribution in 1T-TiSe2

Capturing ultrafast dynamics over a large momentum space is critical for revealing the relationship between the electronic and structural modulations in quantum materials. Here, by performing time- and angle-resolved photoemission spectroscopy measurements at the Synergetic Extreme Condition User Facility (SECUF) equipped with an extreme ultraviolet light source, we reveal the ultrafast dynamics of a charge-density wave (CDW) material, 1T-TiSe2, upon photoexcitation. Pump-induced CDW melting is revealed from two aspects: gap closing of the CDW at the Brillouin zone (BZ) center and weakening of the CDW folded band at the BZ boundary. By comparing the transient electronic structure and spectral weight over a large momentum space, we further reveal the carrier redistribution involving the excitation of electrons from the Gamma point to the M point. This study provides a comprehensive picture of the physics and ultrafast dynamics of a CDW material across the entire BZ.