Conductivity of a two-dimensional electronic crystal over He3-He4 liquid solutions

Abstract

Experimental data on and a theoretical analysis of the conductivity of a two-dimensional Wigner crystal (WC) on the surface of weak solutions of quantum liquids He3-He4 (x<0.25% 3He) are presented. The conductivity is determined using resonance excitation of low-frequency coupled longitudinal phonon-ripplon modes of a WC. A strong temperature dependence of the resistance of a WC, differing substantially from that found previously for a nondegenerate electron gas, is found. At the same time the experimental dependence of the resistance on the impurity concentration is found to be quite weak, which shows that the scattering of transverse phonons by ripplons plays the dominant role in the resistance of a two-dimensional WC for x<0.25%.