Atomistic simulation of the surface energy of spinel MgAl ₂O ₄

Atomistic simulations with atomic potentials including anion polarizibility have been performed for the low-index surfaces of spinel MgAl ₂O ₄ with various terminations. The calculations show that for the most stable surface the surface energy is 2.27 J/m ² for the {100}, about 2.85 J/m ² for the {110}, and 3.07 J/m ² for the {111} orientation. The ratio between the experimental values to the calculated relaxed surface energies is about 1.5. Strong surface relaxation was found for the {110} and {111} orientation but only moderate surface relaxation for the {100} surface.