Regensburg 2025 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 60: Focus Session: Physics of the van der Waals Magnetic Semiconductor CrSBr II (joint session HL/MA)
HL 60.8: Invited Talk
Friday, March 21, 2025, 12:30–13:00, H17
Electric field control of intra- and interlayer excitons in CrSBr — •Nathan Wilson1, Amine Ben Mhenni1, Ferdinand Menzel1, Alain Dijkstra1, Zdenek Sofer2, and Jonathan Finley1 — 1Walter Schottky Institute, TU Munich, Garching, Germany — 2Institute of Chemistry and Technology, Prague, Czech Republic
In the 2D magnetic semiconductor CrSBr, the interplay between a direct bandgap for all layer thicknesses and layered antiferromagnetism with strong magneto-electronic coupling give rise to rich but poorly understood excitonic physics. So far, the presence of two closely spaced conduction bands and existence of both intra and interlayer excitons in multilayers has complicated interpretation of the optical spectrum of its excitons. Here, we study monolayers and bilayers of CrSBr in dual-gated structures, allowing for independent tuning of electric field and charge doping. Our study reveals the existence of the previously unobserved ground state exciton in monolayers, which is darkened both by charge doping and electric field. We find that both intralayer and hybrid intra/interlayer excitons are highly sensitive to the vertical electric field, implying a reasonably large exciton polarizability and control over wavefunction symmetry. With this information, we are able to form a more complete picture of the real space and band character of the excitons in CrSBr.
Keywords: Excitons; 2D semiconductors; 2D magnetic materials; Optical spectroscopy