In-plane relaxation of Cu(111) andAl(111)/α−Al2O3(0001) interfaces

Abstract

The electronic structure and total energy of the Al and Cu alumina interfaces have been calculated with the plane wave pseudopotential method based on Lanczos diagonalization of the Kohn-Sham density matrix. For both interfaces we found in-plane relaxation, resulting in the rotation of the O triangle and expansion of the O-O bonds at the alumina surface. The calculated adhesive energies of the Cu(111)/alumina and Al(111)/alumina interfaces are several times smaller than that of the Nb(111)/alumina interface. The Cu(111)/Al-terminated alumina interface is found to have the smallest adhesive energy which is presumably related to the high degree of spatial delocalization of metal-oxygen bonds at the interface.