Theory of Hot Electrons on the Liquid ⁴He Surface

Theoretical analysis is given of the non-linear transport of electrons bound on the liquid 4 He surface by the classical image force, the external holding field and the repulsive barrier of the liquid. The Boltzmann transport equation is solved in the effective electron temperature approximation, where the electron-ripplon and electron-He vapor interactions are considered as the dominant scattering mechanisms. Inter-subband as well as intra-subband transitions are fully taken into account in order to calculate mobility at high drift electric fields. Good agreement is obtained between theory and available experimental data of high temperature, and dramatic non-linear behaviors are predicted to occur in the low temperature region.