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

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 moiré patterns for topological properties in a twisted hBN/Gr/hBN hybrid heterostructure using tight-binding approximations and DFT calculations. For smaller twist angles below Δθ < 5°, a reconstruction of the band structure is marked by formation of miniband gaps and multiple Dirac points from modification in the moiré 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 Δθ = 0° to a nontrivial phase (C = 1) at Δθ = 1.8°, and switching back to a trivial phase for Δθ > 5°. Our studies reveal twist angle driven topological phase transitions in 2D double moiré heterostructures, underscoring its applications in designing quantum devices.