E. Artacho et J. Zegenhagen, SURFACE-ENERGY AND STABILITY OF STRESS-DRIVEN DISCOMMENSURATE SURFACE-STRUCTURES, Physical review. B, Condensed matter, 52(23), 1995, pp. 16373-16376
A method is presented to obtain ab initio upper and lower bounds to su
rface energies of stress-driven discommensurate surface structures, po
ssibly nonperiodic or exhibiting very large unit cells. The instabilit
y of the stressed, commensurate parent of the discommensurate structur
e sets an upper bound to its surface energy; a lower bound is defined
by the surface energy of an ideally commensurate but laterally straine
d hypothetical surface system. The surface energies of the phases of t
he Si(111):Ga and Ge(111):Ga systems and the energies of the discommen
surations are determined within +/-0.2 eV.