Regensburg 2022 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 29: 2D Materials: Graphene

HL 29.1: Talk

Thursday, September 8, 2022, 09:30–09:45, H36

Twist angle engineering of proximity exchange in graphene/Cr₂Ge₂Te₆ bilayers — •Klaus Zollner and Jaroslav Fabian — Institute for Theoretical Physics, University of Regensburg, 93053 Regensburg, Germany

Van der Waals heterostructures composed of twisted monolayers promise great tunability of electronic, optical, and magnetic properties. The most prominent example is twisted bilayer graphene, exhibiting magnetism and superconductivity due to strong correlations [1]. In addition, twistronics has already demonstrated its potential in tuning proximity spin-orbit coupling in graphene/TMDC heterostructures [2]. In this talk, we present the twist-angle and gate dependence of the proximity exchange coupling in graphene/Cr₂Ge₂Te₆ bilayers from first principles [3]. The proximitized Dirac band dispersions of graphene show a continuous tunability of the ferromagnetic exchange from 4 to −4 meV, when twisting from 0^∘ to 30^∘. Remarkably, at 19.1^∘ the induced exchange coupling becomes even antiferromagnetic. Further tuning is provided by a transverse electric field and the interlayer distance.

This work was supported by DFG SFB 1277, DFG SPP 2244, and the EU Horizon 2020 Research and Innovation Program (Graphene Flagship).

[1] X. Lu et al., Nature 574, 653 (2019). [2] T. Naimer et al., Phys. Rev. B 104, 195156 (2021). [3] K. Zollner and J. Fabian, arXiv:2108.03984 (2021).