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Tuning exciton complexes in twisted bilayer WSe2 at intermediate misorientation

Debnath, R and Sett, S and Kundu, S and Biswas, R and Raghunathan, V and Jain, M and Ghosh, A and Singh, A (2022) Tuning exciton complexes in twisted bilayer WSe2 at intermediate misorientation. In: Physical Review B, 106 (12).

Physical Review B_106-12_2022.pdf - Published Version

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Official URL: https://doi.org/10.1103/PhysRevB.106.125409


Twist angle modifies the band alignment, screening, and interlayer (IL) coupling in twisted bilayers (tBLs) of transition metal dichalcogenides. Intermediate misorientation (twist angles > 15°) bilayers (BLs) offer a unique opportunity to tune excitonic behavior within these concurrent physical mechanisms but are seldom studied. In this paper, we measure many-body excitonic complexes in monolayer (ML), natural BL, and tBL WSe2. Neutral biexciton (XX) is observed in tBL, while being undetected in nonencapsulated ML and BL, demonstrating unique effects of disorder screening in tBLs. The XX as well as charged biexciton (XX-) are robust to thermal dissociation and are controllable by electrostatic doping. Vanishing of momentum-indirect IL excitons with increasing electron doping is demonstrated in tBL, resulting from near alignment of Q′-K and K-K valleys. Intermediate misorientation samples offer a high degree of control of excitonic complexes while offering possibilities of studying exciton-phonon coupling, band alignment, and screening.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Alignment; Dissociation; Excitons; Screening; Transition metals, Band alignments; Bi-layer; Biexcitons; Dichalcogenides; Exciton complexes; Excitonic complexes; Interlayer coupling; Misorientations; Twist angles; Twisted bilayers, Selenium compounds
Department/Centre: Division of Electrical Sciences > Electrical Communication Engineering
Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 12 Oct 2022 11:47
Last Modified: 12 Oct 2022 11:47
URI: https://eprints.iisc.ac.in/id/eprint/77289

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