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Proximity effects constitute a highly promising tool for versatile engineering of the band structure of graphene in van der Waals heterostructures [1]. Particularly promising relevant systems are based on transition metal dichalcogenides [2]. In the paper some approaches to tune the proximity effects in reversible manner will be discussed. A main one is based on charge density wave degree of freedom. Such a low-temperature ordering is known to develop in 1T polytypes of TaS2 and NbS2, enabling to manipulate the band structure of heterostructures in twistronic-like way without physical alteration of the twist angle.
In the paper the DFT calculations-based predictions of proximity effects in graphene band structure emerging in heterostructures with TaS2 [3] and NbS2 and controllable with charge density wave ordering will be presented. Moreover, magnetism in TaS2 [4] will be discussed as yet another mechanism capable of shaping the proximity effects. Also the external electric field will be demonstrated to be an additional useful factor influencing the band structure.
The interpretation of the results will be based on symmetry-based tight-binding Hamiltonians [3]. Special emphasis will be put on proximity-induced Rashba spin-orbit coupling parametrized by characteristic energy and tuneable angle (inducing possible anisotropic Rashba-Edelstein effect).
Acknowledgements: Financial support provided by the University of Łódź under Grant No. 1/IDUB/DOS/2021 is gratefully acknowledged. Polish high-performance computing infrastructure PLGrid (HPC Centers: ACK Cyfronet AGH) is gratefully acknowledged for providing computer facilities and support within computational grant no. PLG/2023/016571.
[1] J. F. Sierra, J. Fabian, R. K. Kawakami, S. Roche and S. O. Valenzuela, Nature Nanotechnology 16, 856 (2021)
[2] M. Gmitra and J. Fabian, Physical Review B 92, 155403 (2015)
[3] K. Szałowski, M. Milivojević, D. Kochan and M. Gmitra, 2D Materials 10, 025013 (2023)
[4] I. Lutsyk, K. Szałowski et al., Nano Research 16, 11528 (2023)