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O: Fachverband Oberflächenphysik

O 68: Focus Session: Time-Resolved Momentum Microscopy

O 68.1: Topical Talk

Thursday, September 8, 2022, 15:00–15:30, H3

Exploring Excitonic Excitations in Momentum Space — •Keshav Dani — Okinawa Inst. of Science and Technology, Graduate University, Onna-son, Japan

Optical techniques have provided us with rich information about the exciton * a two-particle photoexcited state in semiconductors and insulators. Yet, they have left a fundamental degree of freedom of the exciton inaccessible * it*s momentum! In this talk, I will discuss the application of time-resolved photoemission techniques to access the momentum coordinate of excitons in 2D semiconductors, thereby providing us with the formation pathways of momentum-forbidden dark excitons [1], an image of the electron around the hole in the exciton, the observation of the long-predicted anomalous dispersion of the exciton-bound electron [2], the momentum distribution of the exciton-bound hole, and the confinement of the interlayer exciton in a moiré cell [3].

References ( *equal authors) [1] J. Madeo*, M. K. L. Man*, et al. Science 370, 1199 (2020). [2] M. K. L. Man*, J. Madeo*, et al. Science Advances 7, eabg0192 (2021). [3] O Karni*, E. Barr*, V. Pareek*, J. D. Georgaras*, M. K. L. Man*, C. Sahoo*, et al. Nature 603, 247 (2022).