Figure 1

The relaxed atomic structures of the (a) homogeneous bilayer of BiOX/BiOX and (b) heterogeneous bilayer of BiOX1/BiOX2. The violet, red, green, and brown balls represent Bi, O, X1 (Cl), and X2 (Br) atoms, respectively.
The relaxed atomic structures of the (a) homogeneous bilayer of BiOX/BiOX and (b) heterogeneous bilayer of BiOX1/BiOX2. The violet, red, green, and brown balls represent Bi, O, X1 (Cl), and X2 (Br) atoms, respectively.