Crystal-field effects in graphene with interface-induced spin-orbit coupling

Article

关键词: TRANSITION-METAL DICHALCOGENIDES;    DER-WAALS HETEROSTRUCTURE;    ELECTRONIC-PROPERTIES;    MONOLAYER;    OPTOELECTRONICS;    TEMPERATURE;    MANGANITES;    ANISOTROPY;    STATES;   

DOI  :  10.1103/PhysRevB.98.045407

来源: SCIE

【 摘 要 】

We consider theoretically the influence of crystalline fields on the electronic structure of graphene placed on a layered material with reduced symmetry and large spin-orbit coupling (SOC). We use a perturbative procedure combined with the Slater-Koster method to derive the low-energy effective Hamiltonian around the K points and estimate the magnitude of the effective couplings. Two simple models for the envisaged graphene-substrate hybrid bilayer are considered, in which the relevant atomic orbitals hybridize with either top or hollow sites of the graphene honeycomb lattice. In both cases, the interlayer coupling to a crystal-field-split substrate is found to generate highly anisotropic proximity spin-orbit interactions, including in-plane spin-valley coupling. Interestingly, when an anisotropic intrinsic-type SOC becomes sizable, the bilayer system is effectively a quantum spin Hall insulator characterized by in-plane helical edge states robust against the B ychkov-Rashb a effect. Finally, we discuss the type of substrate required to achieve anisotropic proximity-induced SOC and suggest possible candidates to further explore crystal-field effects in graphene-based heterostructures.

【 授权许可】

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