Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 29: Poster: 2D Materials

O 29.25: Poster

Dienstag, 19. März 2024, 12:30–14:30, Poster A

Azimuthal- and valley dependent second harmonic generation response of monolayer MoS2 — •Jin Yu, Tao Yang, R. Kramer Campen, and YuJin Tong — Universität Duisburg-Essen, Fakultät für Physik, Experimentalphysik, Lotharstr. 1, 47057 Duisburg

Transition metal dichalcogenides (TMDCs) offer advantages in terms of rapid information processing speed and low energy consumption compared to conventional electronic components. Understanding how spin-valley locking controls the interaction of TMDCs and light is crucial for optimizing TMDCs for practical applications in quantum technology. In this study, we employed elliptically and circularly polarized lasers to excite monolayers of molybdenum disulfide. Our results reveal significant changes in the disappearance of sixfold symmetry, larger azimuthally dependent second harmonic generation (SHG) intensity extremes, and the rotation of a sixfold pattern due to variations in laser polarization from linear to circular and our data aligns closely with the predictions of the steady-state model. According to the steady-state model, under low-light-intensity excitation conditions, the angle of the sixfold pattern rotation is proportional to the difference in the number of particles between the valleys. This result provides a quantitative understanding of the SHG valley polarization signal.

Keywords: TMDCs; Valleytronics; SHG; Exciton; Spin valley locking effect