Phonon scattering against point defects in the quantal 2D Wigner crystal

We evaluate the mean free path l(ph)(T) of point defects in the triangular Wigner electron crystal in the quantal regime at low temperature T, as dete rmined by scattering against transverse acoustic phonons. On treating the d efect as a fixed scattering center we find l(ph)(T) proportional to T-6 for both a vacancy and an interstitial. From a simple estimate of the proporti onality constant, our results are compatible with electrical resistivity da ta for holes in a very clean semiconductor heterostructure if we assume a d efect concentration of order 10(-2)-10(-3) near melting. (C) 2001 Elsevier Science Ltd. All rights reserved.