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

Abstract

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 determined by scattering against transverse acoustic phonons. On treating the defect as a fixed scattering center we find ℓ ph( 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.