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

We evaluate the mean free path ℓph(T) of point defects in the triangular Wigner electron crystal in the quantal regime at low temperature T, as determined by scattering against transverse acoustic phonons. On treating the defect as a fixed scattering center we find ℓph(T)∝T−6 for both a vacancy and an interstitial. From a simple estimate of the proportionality constant, our results are compatible with electrical resistivity data for holes in a very clean semiconductor heterostructure if we assume a defect concentration of order 10−2–10−3 near melting.