Berlin 2024 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 40: 2D Materials and Heterostructures: Magnetic Properties

HL 40.9: Vortrag

Donnerstag, 21. März 2024, 12:00–12:15, EW 201

Proximity Spin Physics in Twisted van der Waals Heterostructures — •Klaus Zollner¹, Paulo E. Faria-Junior¹, Simão M. João², Branislav K. Nikolić³, and Jaroslav Fabian¹ — ¹University of Regensburg, 93040 Regensburg, Germany — ²Imperial College London, London SW7 2AZ, United Kingdom — ³University of Delaware, Newark, DE 19716, USA

A crucial degree of freedom, to tailor proximity-induced spin interactions in van der Waals heterostructures, is the relative twist angle between the monolayers. We present comprehensive DFT-based results on twist- and gate-tunable proximity spin-orbit and exchange coupling in various 2D material heterostructures. Remarkably, in graphene/Cr₂Ge₂Te₆, the proximity exchange splitting of Dirac states can be reversed upon twisting, from 4 to −4 meV, while keeping the magnetization of Cr₂Ge₂Te₆ fixed [1]. In WSe₂/CrI₃, the valley splitting shows a gigantic tunability, from 0 to 12 meV (≈ 60 Tesla), combining twisting and gating [2]. In graphene/transition-metal-dichalcogenide bilayers, the spin-orbit coupling of proximitized Dirac bands can be tailored by several means [3]. Finally, we demonstrate the emergence of purely radial spin-orbit fields in twisted multilayers. We also relate our findings to experimentally verifiable fingerprints of proximity-induced spin interactions.

We acknowledge funding through DFG SFB 1277, DFG SPP 2244, and EU Horizon 2020 Program (Graphene Flagship).

[1] K. Zollner et al., PRL 128, 106401 (2022). [2] K. Zollner et al., PRB 107, 035112 (2023). [3] K. Zollner et al., arXiv:2310.17907 (2023).

Keywords: 2D Materials; Proximity Effects; Twist Angle; First-Principles Calculations