1. carrier-driven ultrafast coherent phonon generation in monolayer mose2 explored by ab intio approach

Soungmin Bae

Tokyo Institute of Technology, Japan

28 July 2022 Thu 4 pm

                                      IBS Center for Theoretical Physics of Complex Systems (PCS), Administrative Office (B349), Theory Wing, 3rd floor

                                      Expo-ro 55, Yuseong-gu, Daejeon, South Korea, 34126 Tel: +82-42-878-8633                     

Valleytronics have critically boosted fascinating optoelectrical applications by efficiently controlling momentum-locked valley pseudospins, transition metal dichalcogenides (TMDs) are being as the most prominent prototype valleytronic materials manifesting strong carrier-phonon interactions within low dimensionality. In such TMDs, carrier-phonon coupling critically affects the transient dynamics of photoexcited carriers and time scale of such interactions are ultrafast phenomena under sub-10 picoseconds time scale. Coherent phonon measurement using femtosecond pump-probe spectroscopy enables direct tracking of time-transient phonon-related ultrafast carrier dynamics in TMDs such manifested by phonon-mediated intervalley scatterings and bound exciton formations trapping at lattice defects. Coherent phonon generations and related phenomena have been extensively investigated in my recent works by using ab initio calculations, expanding our understanding of the quantum origins of ultrafast carrier dynamics. In my talk, I will introduce my recent ab initio studies that reveals atomistic origins of coherent phonon generation in monolayer MoSe2, which pave the way for unveiling the underlying quantum physics of various ultrafast phenomena.