Phonon–ripplon resonances in two-dimensional electron crystal over liquid helium

Abstract

Electron–ripplon oscillations in a Wigner crystal over liquid helium surface with a charge concentration 1.3·109 cm−2 are investigated experimentally in the temperature range 70–600 mK. The frequency and line width are measured for resonances corresponding to excitation of phonon–ripplon modes in the frequency range 1–20 MHz. The temperature dependence of resonant frequencies is in good agreement with theoretical calculations.