ON THE TRANSIT-TIME OF ELECTRONS IN RESONANT STRUCTURES

A resonance formalism based on the notions of partial decay widths and resonance energy [1] is used to compare the transmission phase time, the dwell time and the Larmor time near resonance energy for coherent processes in one dimension. It turns out that except for the case of full transmission, i.e., the transmission coefficient equal to unity, the above notions do not yield an appropriate definition for the transit time of an electron through the system. On the other hand, the resonance formalism is used to support an alternative definition of the transit time given by tau(tr) = 1/4(hBAR/GAMMA(n)0 + hBAR/GAMMA(n)L) where GAMMA(n)0 and GAMMA(n)L stand for the two partial decay widths associated to the corresponding two channels in a one-dimensional system [2]. For a double-barrier structure the time scale provided by tau(tr) turns out to be inversely proportional to the tunneling current integrated across the resonance width.