ORIGIN OF CURRENT BROADENING IN RESONANT-TUNNELING VIA LOCALIZED STATES

It is found that in electron resonant tunneling via localised states, the current exhibits a very strong temperature dependence and power no nconservation. This subtle behaviour is due to the impurity states ind uced tunneling which is subsequently renormalised by an overlap integr al of many-electron states in the emitter. By using a temperature-depe ndent dynamical approach, an analysis of this interesting tunneling pr ocess is performed. It is found that the temperature dependence of the current has a very different origin from the thermal activation. It i s also found that plasmon excitation in the emitter further renormalis es the tunneling current by a factor of two to three orders of magnitu de.