腾讯会议ID：379-192-423
会议密码：0514
主持人：孟胜 研究员
联系人：傅琦 (fuqi@iphy.足球比赛实时比分cn)
Abstract:
Time-resolved methods based on ultrafast laser enable the excitation of electronic systems into nonequilibrium states, and allow for the probe complex many-body effects and the control of transient metastable phases, which are inaccessible 足球比赛实时比分 steady-state experiments. 足球比赛实时比分 this talk, I will first briefly introduce our earlier work on ultrafast charge-density-wave dynamics by time-resolved ARPES (EUV). Then I will present our recent progresses by time-resolved optical spectroscopy (VI-NIR). We observe interband-transition-induced high-energy electronic excitations 足球比赛实时比分 a bilayer nickelate superconductor La3Ni2O7, associated with two density-wave gaps and correlated with distinct coherent phonons. The charge-transfer gap 足球比赛实时比分 cuprate parent compounds, which has been proposed to anticorrelate with superconducting transition, undergoes ultrafast renormalization under photoexcitation. The interfacial electron-phonon coupling is directly observed 足球比赛实时比分 FeSe/STO. Notably, ultrafast laser pulses with circular polarization enable the excitation and monitoring of chirality dependent valleytronics, coherent optical Stark effect and biexcitons 足球比赛实时比分 2D transition metal dichalcogenides. 足球比赛实时比分 the end, I will introduce low-energy excitations probed by terahertz (THz), including the oxygen vacancy modes 足球比赛实时比分 an electrolyte material ZrO2, and low-frequency phonon dynamics 足球比赛实时比分 black phosphorus.
Brief CV of Dr. Haiyun Liu:
Dr. Haiyun Liu received his Ph.D degree 足球比赛实时比分 condensed matter physics 足球比赛实时比分 2010 from Institute of Physics, Chinese Academy of Sciences, under the supervision of Prof. Xingjiang Zhou. After graduation, he worked as a postdoctoral fellow and beamline scientist 足球比赛实时比分 Prof. Andrea Cavalleri's group at University of Hamburg and Max Planck Research Department for Structural Dynamics (MPSD). 足球比赛实时比分 2019, he joined Beijing Academy of Quantum Information of Sciences as an associate professor. His research focuses on ultrafast dynamics of nonequilibrium states, including many body effects and transient phase transitions 足球比赛实时比分 high-temperature superconductors, two-dimensional transition metal dichalcogenides, density-wave materials, and related systems.