Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 22: Focus Session: Young Semiconductor Forum
HL 22.18: Poster
Tuesday, March 19, 2024, 11:00–15:30, Poster F
Broken symmetries in two-dimensional materials probed by nonlinear optoelectronic transport — •Christoph Kastl — Walter Schottky Institute and Physik-Department, Technical University of Munich, Germany — Munich Center for Quantum Science and Technology (MCQST), Munich, Germany
I will present examples of (un)intentionally broken symmetries in van der Waal materials and the resulting nonlinear optoelectronic transport. For MoTe2, photocurrent imaging reveals a disordered transition between the monoclinic phase to the low-temperature orthorhombic phase, where ultrafast photocurrents originate from the local breaking of the electronic symmetries (2D Mater. 2022, 9, 011002). In graphene-based circuits, we address gate-tunable, non-linear transport arising from strong spin-orbit coupling, which may be used to manipulate spin-polarized carriers by both optical and electrical means. In commensurate graphene/Bi2Te2Se interfaces, we find an enhanced helicity-dependent photocurrent due to the peculiar spin-orbit proximity of the commensurate alignment (ACS Nano 2022, 16, 12338-12344). In graphene/WTe2, we demonstrate optical detection of current-induced spin polarisations related to a nonlinear anomalous Hall effect in the heterostructure (Nat. Commun. 2022, 13, 3152). Finally, I will discuss recent work towards top-down control of electronic symmetries by nanofabricaton of lateral superlattice structures in van der Waals materials. The research is supported through the European Union’s Horizon Europe Research and Innovation Programme under Grant Agreement No 101076915 (2DTopS).
Keywords: 2D materials; spin-orbit coupling; nonlinear transport