Switching between Topological Phases in Double Moire hBN-Graphene-hBN Heterostructure with Twist Angles

Renu and K Katin and M Muruganathan and R Kumar, JOURNAL OF PHYSICAL CHEMISTRY C, 129, 18211-18221 (2025).

DOI: 10.1021/acs.jpcc.5c03591

Twistronics in two-dimensional (2D) van der Waals heterostructures carries enormous potential for probing emergent quantum phases and tunable electronic behavior. In this study, we investigate the double moire patterns for topological properties in a twisted hBN/Gr/hBN hybrid heterostructure using tight-binding approximations and DFT calculations. For smaller twist angles below Delta theta < 5 degrees, a reconstruction of the band structure is marked by formation of miniband gaps and multiple Dirac points from modification in the moire wavelength and interference patterns. Closing and reopening of the band gaps are noted with twist angles. Further analyses of the Berry curvatures confirm a topological phase transition from a trivial (Chern number = 0) at Delta theta = 0 degrees to a nontrivial phase (C = 1) at Delta theta = 1.8 degrees, and switching back to a trivial phase for Delta theta > 5 degrees. Our studies reveal twist angle driven topological phase transitions in 2D double moire heterostructures, underscoring its applications in designing quantum devices.

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