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MA: Fachverband Magnetismus
MA 43: Spin-Dependent Phenomena in 2D
MA 43.2: Vortrag
Donnerstag, 12. März 2026, 10:00–10:15, POT/0112
Electric-field tunable valley excitons in proximity coupled WSe2/CrI3 heterostructures — Felix Hellenkamp1, •Yiheng Li1, Marc Schütte1, Kenji Watanabe2, Takashi Taniguchi3, Lutz Waldecker1, Christoph Stampfer1,4, and Bernd Beschoten1 — 12nd Institute of Physics and JARA-FIT, RWTH Aachen University, Germany — 2National Institute for Materials Science, Tsukuba, Japan — 3International Center for Materials Nanoarchitectonics, NIMS — 4PGI-9, Forschungszentrum Jülich, Jülich, Germany
Two-dimensional (2D) transition metal dichalcogenides have attracted significant interest due to their unique optical properties. The possibility to address the K and K’ valley selectively via σ+ and σ− polarized light enables optical initialization and readout of the valley degree of freedom. The valley degeneracy can be lifted via magnetic proximity coupling to a 2D magnet such as CrI3. However, in the heterostructures the resulting exciton splitting lacks tunability, limiting its applicability in device architectures that demand adjustable valley splitting. Our work shows a large tunability of the exciton splitting in a WSe2/CrI3 heterostructure via external displacement fields. Reflection contrast measurements show a displacement field induced change in the exciton resonance energy which is asymmetric with respect to the excitons at the K and K’ valleys, leading to a 35% increase in exciton splitting at a displacement field of -0.4V/nm. We attribute the change in resonance energy to a reduction in the optical bandgap, caused by a displacement-field-induced modification in the band alignment.
Keywords: Proximity Coupling; Exciton Splitting; WSe2/CrI3; Valleytronics; 2D Semiconductors