Fig. 1. (Color online) The top view of free B atoms at different adsorption sites with one h-BN buffer layer. (a–e) show the initial adsorption sites and (f–j) show the final configurations after optimization.

Fig. 2. (Color online) The top view of free N atoms at different adsorption sites with one h-BN buffer layer. (a–e) show the initial adsorption sites and (f–j) show the final configurations after optimization.

Fig. 3. (Color online) (a–c) The top view and (d–f) front view of the optimized adsorption positions for B atom on the surface with different buffer layers. The S_C site is chosen as the initial absorption site for the B atom.

Fig. 4. (Color online) (a–c) The top view and (d–f) front view of the optimized adsorption positions for the N atom on the surface with different buffer layers. The S_C site is chosen as the initial absorption site for the B atom.

Fig. 5. (Color online) The probability distribution functions of atomic displacements projected onto the xy plane for (a) the B atom at 300 K, (b) the N atom at 300 K, (c) the B atom at 1573 K and (d) the N atom at 1573 K, respectively. The color scale indicates the distribution probability. The positions of B and N atoms of the buffer layer are marked.

Fig. 6. The MSD curves of (a) B atoms and (b) N atoms on the buffer layer surface at different temperatures.

Table 1. The formation energies (eV) of free B or N atoms at the surface sites of the Al₂O₃/h-BN-buffer-layer model.

Table 2. The formation energies of free B and N atoms at the same position on the surface of the Al₂O₃/h-BN-buffer-layer model in a different number of buffer layers.

Table 3. Diffusion coefficients of free atoms on the surface of the model at different temperatures.