Chatterjee, S and Dandu, M and Dasika, P and Biswas, R and Das, S and Watanabe, K and Taniguchi, T and Raghunathan, V and Majumdar, K (2023) Harmonic to anharmonic tuning of moiré potential leading to unconventional Stark effect and giant dipolar repulsion in WS2/WSe2 heterobilayer. In: Nature Communications, 14 (1).
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Abstract
Excitonic states trapped in harmonic moiré wells of twisted heterobilayers is an intriguing testbed for exploring many-body physics. However, the moiré potential is primarily governed by the twist angle, and its dynamic tuning remains a challenge. Here we demonstrate anharmonic tuning of moiré potential in a WS2/WSe2 heterobilayer through gate voltage and optical power. A gate voltage can result in a local in-plane perturbing field with odd parity around the high-symmetry points. This allows us to simultaneously observe the first (linear) and second (parabolic) order Stark shift for the ground state and first excited state, respectively, of the moiré trapped exciton - an effect opposite to conventional quantum-confined Stark shift. Depending on the degree of confinement, these excitons exhibit up to twenty-fold gate-tunability in the lifetime (100 to 5 ns). Also, exciton localization dependent dipolar repulsion leads to an optical power-induced blueshift of ~ 1 meV/μW - a five-fold enhancement over previous reports.
| Item Type: | Journal Article |
|---|---|
| Publication: | Nature Communications |
| Publisher: | Nature Research |
| Additional Information: | The copyright for this article belongs to the Authors. |
| Keywords: | article; parity |
| Department/Centre: | Division of Electrical Sciences > Electrical Communication Engineering |
| Date Deposited: | 27 Nov 2023 09:33 |
| Last Modified: | 27 Nov 2023 09:33 |
| URI: | https://eprints.iisc.ac.in/id/eprint/82867 |
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