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 pho...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-TiSe_(2),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 theГpoint to the M point.This study provides a comprehensive picture of the physics and ultrafast dynamics of a CDW material across the entire BZ.展开更多
基金supported by the Synergetic Extreme-Condition User Facility(SECUF)the National Key R&D Program of China(Grant Nos.2021YFA1400100,2020YFA0308800,and 2022YFA1604200)+2 种基金the National Natural Science Foundation of China(Grant Nos.12234011,92250305,52388201,11725418,and 11427903)supported by the China Postdoctoral Science Foundation(Grant Nos.2022M721886 and BX20230187)the Shuimu Tsinghua Scholar Program。
文摘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-TiSe_(2),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 theГpoint to the M point.This study provides a comprehensive picture of the physics and ultrafast dynamics of a CDW material across the entire BZ.
