Seminarium "Modeling of Complex Systems"

Synthesis of van der Waals heterostructures enables efficient engineering of graphene band structure owing to proximity effects emerging in such systems [1]. Transition metal dichalcogenides constitute a particularly promising family of heterostructure components, leading to acquisition of novel functionalities by graphene [2]. The paper will discuss some approaches to control the mentioned proximity effects in reversible manner. A main considered mechanism will be based on charge density wave degree of freedom. Such alow-temperature ordering develops in 1T polytypes of TaS2 and NbS2 and can be utilized to manipulate the band structure of heterostructures in twistronic-like way (without physical alteration of the twist angle).The paper will present the predictions of proximity effects in graphene band structure, emerging in heterostructures with TaS2 [3] and NbS2, based on DFT calculations. Charge density wave [3] and magnetic [4] orderings will be demonstrated to serve as possible tuning knobs useful for controlling the proximity effects. The influence of the external electric field on the band structure will also be discussed.The results of DFT calculations will be interpreted on the basis of symmetry-based tight-binding Hamiltonians [3]. Particular emphasis will be put on proximity-induced Rashba spin-orbit coupling parametrized not only by a characteristic energy, but also with a tunable angle (inducing a 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 computinginfrastructure 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 (2021) 856.[2] M. Gmitra and J. Fabian, Physical Review B 92 (2015) 155403.[3] K. Szałowski, M. Milivojević, D. Kochan and M. Gmitra, 2D Materials 10 (2023) 025013.[4] I. Lutsyk, K. Szałowski et al., Nano Research 16 (2023) 11528.