State- and momentum-dependent nonlinear Stark effect of interlayer excitons in bilayer WSe$_2$

Fuente: arXiv
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Main Authors: Sevik, Cem, Torun, Engin, Milosevic, Milorad V., Paleari, Fulvio
Format: Preprint
Published: 2025
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_version_ 1866915161278775296
author Sevik, Cem
Torun, Engin
Milosevic, Milorad V.
Paleari, Fulvio
author_facet Sevik, Cem
Torun, Engin
Milosevic, Milorad V.
Paleari, Fulvio
contents Interlayer excitons in van der Waals heterostructures offer rich collective phases, prospective optoelectronic applications, and versatile tunability, where control by electronic means is particularly relevant and practical. Here, in the case of bilayer WSe$_2$, we reveal how layer localization of excitons governs their response to an external electric field. Using Many-Body Perturbation Theory, we calculate the exciton dispersion for different stacking symmetries under applied electric field and/or strain, in order to map the landscape of competing low-energy excitons in four distinct finite-momentum valleys. While intralayer excitons are not affected by the electric field, some interlayer ones exhibit a nonlinear Stark shift that becomes linear after a critical threshold. The degree of nonlinearity is a direct measure of the layer hybridization of the electronic subcomponents of the exciton. Our findings explain the peculiar Stark-shift regimes observed in recent experiments, the nature of (anti)symmetric spectral shifts around zero field, and the sensitivity of dipolar excitons to external perturbations, all highly relevant to their further applications in excitonic condensates, optoelectronics devices and quantum emitters.
format Preprint
id arxiv_https___arxiv_org_abs_2502_13861
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle State- and momentum-dependent nonlinear Stark effect of interlayer excitons in bilayer WSe$_2$
Sevik, Cem
Torun, Engin
Milosevic, Milorad V.
Paleari, Fulvio
Mesoscale and Nanoscale Physics
Optics
Interlayer excitons in van der Waals heterostructures offer rich collective phases, prospective optoelectronic applications, and versatile tunability, where control by electronic means is particularly relevant and practical. Here, in the case of bilayer WSe$_2$, we reveal how layer localization of excitons governs their response to an external electric field. Using Many-Body Perturbation Theory, we calculate the exciton dispersion for different stacking symmetries under applied electric field and/or strain, in order to map the landscape of competing low-energy excitons in four distinct finite-momentum valleys. While intralayer excitons are not affected by the electric field, some interlayer ones exhibit a nonlinear Stark shift that becomes linear after a critical threshold. The degree of nonlinearity is a direct measure of the layer hybridization of the electronic subcomponents of the exciton. Our findings explain the peculiar Stark-shift regimes observed in recent experiments, the nature of (anti)symmetric spectral shifts around zero field, and the sensitivity of dipolar excitons to external perturbations, all highly relevant to their further applications in excitonic condensates, optoelectronics devices and quantum emitters.
title State- and momentum-dependent nonlinear Stark effect of interlayer excitons in bilayer WSe$_2$
topic Mesoscale and Nanoscale Physics
Optics
url https://arxiv.org/abs/2502.13861