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HL: Fachverband Halbleiterphysik
HL 40: 2D Semiconductors and van der Waals Heterostructures IV
HL 40.9: Vortrag
Mittwoch, 19. März 2025, 17:45–18:00, H15
Exploring the valley splitting and valley dynamics of WSe2 proximity-exchange coupled to CrI3 — •Natalie Kuhn1, Marc Schütte1, Jo Henri Bertram1, Frank Volmer1, K. Watanabe2, T. Taniguchi3, Christoph Stampfer1,4, Lutz Waldecker1, and Bernd Beschoten1 — 12nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany — 2Research Centre for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan — 3International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan — 4Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
Proximity exchange coupling between 2D magnets and monolayers of transition metal dichalcogenides (TMDs) can lift valley degeneracy of the TMD. This is promising for the field valleytronics, as valley splitting is expected to increase valley lifetimes.
In this study, we investigate the proximity exchange coupling in van der Waals heterostructures made of monolayer WSe2 and few-layer CrI3, a 2D antiferromagnet. The proximity-induced valley splitting of WSe2 is spatially probed by reflection contrast measurements of WSe2 excitons. We observe distinctly different regions in WSe2 identified by their reversed valley splitting. Their origin is explored by their magnetic field dependent reversals, i.e. hysteresis curves that are induced by reversing the magnetization of the interface layer of CrI3. Using time-resolved Kerr rotation measurements we find a strong enhancement of WSe2 valley lifetimes of the spin split valence bands.
Keywords: Van der Waals heterostructures; 2D Magnetism; Proximity Exchange Interaction; Transition Metal Dichalcogenides