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Experimental observation of spin−split energy dispersion in high-mobility single-layer graphene/WSe2 heterostructures

Tiwari, P and Jat, MK and Udupa, A and Narang, DS and Watanabe, K and Taniguchi, T and Sen, D and Bid, A (2022) Experimental observation of spin−split energy dispersion in high-mobility single-layer graphene/WSe2 heterostructures. In: npj 2D Materials and Applications, 6 (1).

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Official URL: https://doi.org/10.1038/s41699-022-00348-y


Proximity-induced spin–orbit coupling in graphene has led to the observation of intriguing phenomena like time-reversal invariant Z2 topological phase and spin-orbital filtering effects. An understanding of the effect of spin–orbit coupling on the band structure of graphene is essential if these exciting observations are to be transformed into real-world applications. In this research article, we report the experimental determination of the band structure of single-layer graphene (SLG) in the presence of strong proximity-induced spin–orbit coupling. We achieve this in high-mobility hexagonal boron nitride (hBN)-encapsulated SLG/WSe2 heterostructures through measurements of quantum oscillations. We observe clear spin-splitting of the graphene bands along with a substantial increase in the Fermi velocity. Using a theoretical model with realistic parameters to fit our experimental data, we uncover evidence of a band gap opening and band inversion in the SLG. Further, we establish that the deviation of the low-energy band structure from pristine SLG is determined primarily by the valley-Zeeman SOC and Rashba SOC, with the Kane–Mele SOC being inconsequential. Despite robust theoretical predictions and observations of band-splitting, a quantitative measure of the spin-splitting of the valence and the conduction bands and the consequent low-energy dispersion relation in SLG was missing—our combined experimental and theoretical study fills this lacuna.

Item Type: Journal Article
Publication: npj 2D Materials and Applications
Publisher: Nature Research
Additional Information: The copyright for this article belongs to the Author(s).
Keywords: Dispersions; Energy gap; III-V semiconductors, Energy dispersions; Filtering effects; High mobility; Single layer; Spin splittings; Spin-orbit couplings; Spin-orbitals; Split energy; Time-reversal; Topological phase, Graphene
Department/Centre: Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 14 Nov 2022 05:49
Last Modified: 14 Nov 2022 05:49
URI: https://eprints.iisc.ac.in/id/eprint/77756

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