LIGHT-EMISSION FROM STM BY MEANS OF THE CHERENKOV EFFECT

In the present work we have shown experimentally that the light emissi on intensity from a STM tunneling junction depends exponentially on th e tunneling distance, and we believe that the decay constant is equal to the mean wave vector of the surface plasmons excited by the tunneli ng electrons. Our estimation of the plasmon phase velocity shows that this is about two times smaller than the Fermi velocity of the electro ns inside the metal. Theoretically, we have developed a description of the phenomenon based on resonant Cherenkov interaction between the tu nneling electrons and the propagating surface plasmons. Our calculatio ns of the dispersion law of the surface plasmons and the quantum effic iency for plasmon emission by the tunneling electrons are in qualitati ve agreement with the experimental data.