Fig. 4: Underlying mechanism of stacking-dependent topology in multi-SL MBT films.

a The intralayer and interlayer hopping matrix in the four-band model hamiltonians. b Comparison of topological invariants (C) and band gaps between first-principles calculations and model hamiltonians. c Isosurface of charge density difference (Δρ) in the CAC- and ABC-stacking orders, respectively. d, e Schematic illustrations of topological phases in distinct stacking orders of 3-SL and 4-SL MBT films, respectively.