Accurate surface energies from first principles

The absolute values of solids' surface energies are among the least well-known physical quantities, despite their fundamental importance. Experimental values obtained by various methods often differ by over 100%, mostly because the measurements are indirect and complicated. Reliable computational methods for predicting surface energies would therefore be extremely valuable. Here we assess the utility of using exact exchange (EXX) in conjunction with the many-electron perturbation theory extension of density functional theory, i.e., the random phase approximation (RPA), when predicting surface energies. The EXX + RPA approach was used to calculate the surface energies and cleavage properties of LiH, Mg, Pb, MgO, and NiAl, materials for which reliable experimental surface energies are available. The calculated values agreed well with the experimental data in all cases, suggesting that the longstanding problem of reliably predicting surface energies has been solved.