LINEWIDTHS OF RESONANCES IN A 2-DIMENSIONAL WIGNER LATTICE ON A LIQUID-HELIUM SURFACE

The linewidths of long-wavelength longitudinal and intermediate-wavelength transverse phonon resonances of a two-dimensional Wigner lattice are calculated. The dominant scattering is umklapp scattering involving ripplons, which is restricted by the large mean square displacement of the electrons. The dependences of the linewidths on density, temperature, and phonon wave vector are very different from that in the gas, and large variations in the linewidths are predicted near the melting temperature for small holding fields. © 1979 The American Physical Society.