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HL: Fachverband Halbleiterphysik

HL 33: 2D Materials and Heterostructures: Optoelectronics

HL 33.2: Talk

Wednesday, March 20, 2024, 15:15–15:30, EW 201

Strong field valleytronics in bulk MoS2 — •Igor Tyulnev¹, Álvaro Jiménez-Galán², Julita Poborska¹, Lenard Vamos¹, Rui F. Silva³, Philip St. J. Russell^4,5, Francesco Tani⁴, Olga Smirnova^2,6, Misha Ivanov^2,7,8, and Jens Biegert^1,9 — ¹ICFO, Barcelona, Spain — ²MBI, Berlin, Germany — ³ICMM, Madrid, Spain — ⁴MPL, Erlangen, Germany — ⁵FAU, Erlangen, Germany — ⁶TU, Berlin, Germany — ⁷HU, Berlin, Germany — ⁸Imperial College, United Kingdom — ⁹ICREA, Barcelona, Spain

Light field control over condensed matter allows the tailoring of material properties and exploits topology with which classical and quantum operations can be realized in next-generation devices. At this forefront are valleytronics which exploit the valley degree of freedom to provide an optical switch between extrema in the band structure. Resonant excitation distinguishes these valleys through selection rules derived from symmetry breaking of time inversion by circular polarized light fields and of space inversion in monolayer materials. Thus, requiring not only specific excitation wavelengths but also limiting possible material platforms. In this work, we, for the first time, validate a novel, off-resonant approach to valley control based on the synthesis of a bi-circular field which by symmetry matching 2H-MoS2 controls the band structure. We demonstrate that strong-field valley control is possible, universal and, at optical speeds, unlocks a path towards engineering efficient, multilayer devices operating on sub-optical cycle timescales.

Keywords: valleytronics; TMDC; topology; trefoil; bandgap engineering