Effect of Intervalley Interaction on Band Topology of Commensurate Graphene/EuO Heterostructures

  • Authors:
    Shanshan Su (UC/Riverside), Yafis Barlas (UC/Riverside), Junxue Li (UC/Riverside), Jing Shi (UC/Riverside), Roger Lake (UC/Riverside)
    Publication ID:
    Publication Type:
    Received Date:
    Last Edit Date:
    2382.004 (University of California/Riverside)


Recent experiments demonstrating proximity induced ferromagnetism in graphene motivate this study of commensurate graphene/EuO heterostructures. Due to the commensurability of graphene with the (111)-EuO layer, graphene’s Dirac points are mapped to the Γ point of the commensurate Brillouin zone. The Eu atoms not only induce proximity exchange on the graphene layer, but they also introduce intervalley interactions resulting in a nonlinear dispersion at Γ. We develop a model Hamiltonian, consistent with the lattice symmetries, that includes proximity induced exchange splitting, spin-orbit coupling, and intervalley interactions with parameters fitted to ab initio calculations. The intervalley interaction opens up a trivial gap preventing the system from
crossing into a nontrivial state. The model Hamiltonian is analyzed to determine the conditions under which the heterostructures can exhibit topologically nontrivial bands.

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