Fig. 6.

(A) Band structure of the continuum model with parameters mentioned in the main text. Blue lines indicate $-K$-valley bands, and red lines indicate $+K$-valley bands. The black dots represent the DFT bands computed for the heterobilayer at displacement field $-0.3$ V/nm (dashed lines are states originating from the Gamma pocket). A, Inset shows the avoided crossing due to interlayer hybridization near $\kappa$. (B) The direct gap between the first two $-K$-valley bands at $\mathit{k}=\mathit{\kappa }$ and minimized over $\mathit{k}$, as a function of $\mathrm{\Delta }{E}_g$. The first band has a nontrivial Chern number for $\mathrm{\Delta }{E}_g<40$ meV.