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arXiv · 2503.11927

Tunable resonant s-p mixing of excitons in van der Waals heterostructures

Jiayu David Cao·Konstantin S. Denisov·Igor Zutic
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Abstract

Excitonic states of tightly-bound electron-hole pairs dominate the optical response in a growing class of two-dimensional (2D) materials and their van der Waals (vdW) heterostructures. In transition metal dichalcogenides (TMDs) a useful guidance for the excitonic spectrum is the analogy with the states in the 2D hydrogen atom. From our symmetry analysis and solving the Bethe-Salpeter equations we find a much richer picture for excitons and predict their tunable resonant s-p mixing. The resonance is attained when the subband splitting matches the energy difference between the 1s and 2p+ (or 2p-) excitons, resulting in the anticrossing of the spectral lines in the absorption as a function of the subband splitting. By focusing on TMDs modified by magnetic proximity, and gated 3R-stacked bilayer TMD, we corroborate the feasibility of such tunable spin splitting. The resulting tunable and bright s-p excitons provide unexplored opportunities for their manipulation and enable optical detection of Rashba or interlayer coupling in vdW heterostructures.

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Jiayu David Cao, Konstantin S. Denisov, Igor Zutic. 2025-03-15. Tunable resonant s-p mixing of excitons in van der Waals heterostructures. https://doi.org/10.1103/kmsm-h1wc

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