We present the first X-ray diffraction structure analysis of the reconstructed diamond (111) surface. The atomic geometry is obtained from the distribution of diffracted intensities along integer-order rods of Bragg scattering perpendicular to the surface. Of all the geometries considered, an atomic arrangement featuring tilted chains of p-bonded surface atoms with distortions in subsurface layers is found to provide the best agreement between the calculated and measured structure factors. The tilted-chain topology explains the origin of the observed surface band gap, but it is at variance with recent theoretical predictions based on the local density approximation.

Surf. Sci.

Huisman, W. J., Lohmeier, M., van der Vegt, H. A., Peters, J. F., de Vries, S. A., Vlieg, E., … van der Veen, J. F. (1998). Evidence for tilted chains on the diamond (111)-2x1 surface. Surf. Sci., 396, 241–252.