ELECTRON-ESCAPE FROM THE IMAGE-POTENTIAL-INDUCED SURFACE-STATES ON LIQUID-HELIUM

Electron escape from the two-dimensional surface state is studied for liquid 4He and 3He surfaces. Experimental conditions are established under which “proper” signals are obtained to give the intrinsic escape rates. The escape rates in the temperature range 1.1 > T > 0.9 K for the 4He surface and 0.6 > T > 0.44 K for the 3He surface show the theoretically expected thermalactivation-type temperature dependence. In the present experimental configuration, the measured escape rate at higher electron densities explicitly demonstrates the electron correlation effect. A simple model is presented to account for the correlation effect on the binding energy of the surface electrons.