Influence of driving electric field on electron-ripplon resonance in 2D electron crystal

Resonance features in the conductivity of a 2D electron crystal over liquid helium are studied experimentally depending on driving electric field. The experiment has been carried out at temperature T = 75 mK for the crystal with surface electron density ns = 8 × 108 cm−2 in the frequency range 4–7 MHz where the resonance mode (0,1) of coupled electron-ripplon oscillations can be excited in the experimental cell. It is found that the resonance amplitude decreases as the exciting voltage increases. Additional features of the resonance curve are observed at frequencies lower than the (0,1) mode frequency. The results are analyzed within Monarkha’s theory which takes into account an influence of non-linearity of interaction between electrons and liquid surface on the dynamics of 2D electron crystal moving along the surface of liquid helium.