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Magnetic proximity induced valley-contrasting quantum anomalous Hall effect in a graphene- CrBr3 van der Waals heterostructure

Bora, M and Behera, SK and Samal, P and Deb, P (2022) Magnetic proximity induced valley-contrasting quantum anomalous Hall effect in a graphene- CrBr3 van der Waals heterostructure. In: Physical Review B, 105 (23).

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Official URL: https://doi.org/10.1103/PhysRevB.105.235422


The magnetic proximity effect is an imperative tool to comprehend the valley contrasting quantum anomalous Hall (QAH) effect in van der Waals (vdW) heterostructure. The introduction of magnetic exchange and spin orbit interaction together enables to realize topological phases, with a particular emphasis on an interface can be envisioned towards dissipationless electronics. Herein, the proximity coupled valley contrasting QAH effect is predicted in vdW heterostructure consisting of graphene and a ferromagnetic (FM) semiconductor CrBr3 with the implication of relativistic effect, from the ab initio density functional theory (DFT) simulation. The valley contrasting QAH effect is observed with a nonzero Chern number at a high-symmetry point stemming from Berry curvature and Wannier charge center (WCC), leading to a topologically nontrivial state. The occurrence of strong magnetic proximity coupling between graphene and CrBr3 monolayer is realized intrinsically, from shifting of Hall coefficient value near Fermi level. The opening of the global band gap (178 meV) is observed with the inclusion of spin orbit coupling (SOC). The anomalous Hall conductivity (AHC) demonstrates the presence of two maxima peaked at valley K′ and K. The observation of AHC is mainly dominated by nonzero surface charge and localized potential at the heterointerface due to proximity interaction. The Fermi level is found to be located exactly inside the nontrivial global band gap, which can be tuned effectively by applying the external electric field or by introducing a staggered sublattice potential. This robustness makes experimental fabrication highly favorable for developing a valley contrasting QAH device prototype.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: The copyright for this article belongs to the American Physical Society.
Keywords: Bromine compounds; Chromium compounds; Density functional theory; Electric fields; Energy gap; Heterojunctions; Landforms; Quantum Hall effect; Topology; Van der Waals forces, Anomalous hall effects; Hall conductivity; Magnetic exchange; Magnetic proximity; Magnetic spin; Proximity coupled; Proximity effects; Spin-orbit interaction; Topological phase; Van der Waal, Graphene
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Date Deposited: 28 Jul 2022 05:52
Last Modified: 28 Jul 2022 05:52
URI: https://eprints.iisc.ac.in/id/eprint/75031

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