The surface relaxation process of the nonpolar (112¯0) surfaces of AlN and α-SiC has been studied by means of periodic Hartree-Fock total-energy calculations on two-dimensional slabs. A relaxation pattern analogous to those found experimentally for other wurtzite-structure semiconductors is predicted for both AlN and α-SiC. Our calculations indicate that ionicity is an important factor determining the extent of relaxation: the more covalent the solid is, the larger are the effects of relaxation on its surface structure. © 1996 The American Physical Society.

• Received 27 April 1995

DOI:https://doi.org/10.1103/PhysRevB.53.4933