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HL: Fachverband Halbleiterphysik

HL 20: Poster I

HL 20.9: Poster

Dienstag, 10. März 2026, 18:00–20:00, P1

Graphene/WSe₂ heterostructures for optical investigation of proximity spin-orbit coupling — •Ernst Knöckl, Matthias Klein, Alexander Holleitner, and Christoph Kastl — Walter Schottky Institute, School of Natural Sciences, Technical University of Munich

We investigate proximity-induced spin-orbit coupling (SOC) in graphene/WSe₂ heterostructures using the circular photogalvanic effect (CPGE) as a symmetry-selective, experimentally simple optical probe of spin-valley-locked band textures [1]. By measuring helicity-dependent photocurrents as a function of gate voltage, excitation energy, and device geometry, we aim to disentangle Rashba and valley-Zeeman SOC contributions and to extract their magnitude and sign as a function of the graphene-WSe₂ twist angle. A key requirement is the fabrication of large, clean, and field-effect-gateable graphene/TMDC heterostructures. To this end, we demonstrate a modified dry-transfer process based on specifically prepaired polydimethylsiloxane (PDMS) stamps [2]. We further determine the relative twist angle using Raman spectroscopy and second-harmonic generation (SHG) spectroscopy.
[1] Kiemle, Jonas, et al. ACS nano 16.8, 12338-12344 (2022)

[2] Jain, A. et al. Nanotechnology 29.26, 265203 (2018)

Keywords: spin-orbit coupling; proximity effect; twist angle; photocurrent