The effect of defects upon the sliding friction of 1-, 2- or 3-dimensional elastic solids was studied. It was shown that, for 1-dimensional or 2-dimensional solids, perturbation theory broke down at low sliding velocities. In the case of a 1-dimensional solid with a low concentration of point defects, an exact solution for the sliding friction was presented which was valid for arbitrary temperatures and strengths of the defect potential.

B.N.J.Persson, A.I.Volokitin: Journal of Physics - Condensed Matter, 1997, 9[14], 2869-89