Observation of correlations in tunneling of surface-state electrons

We measured the escape rates of surface-state electrons from an electron layer confined at the liquid-helium-vacuum interface in the temperature range of 30-450 mK, for densities (0.02-2.2)×10 8 cm -2 . We compared the measured escape rates with calculated tunneling rates in a model where the interactions between the escaping electron and the other electrons are described by an effective single-particle potential. Below 200 mK the escape rates were temperature independent. The single-particle rates were enhanced exponentially as the density was increased up to a critical density n c . In this regime the calculated and measured rates were in good agreement