Resonant tunneling in a multi-channel wire

Abstract

We calculate analytically the transmission coefficient through two delta function barriers in a quasi-one-dimensional wire as the Fermi energy and distance between scatterers are varied. In a purely one-dimensional or single-mode system, the transmission coefficient is periodic as a function of distance between scatterers with successive resonances separated by half the wavelength of the incident electron. In a two-mode system we find unusual modifications to this result when the Fermi energy is near the second subband minimum. First, the presence of the evanescent mode causes successive resonances in the transmission coefficient to be separated by a full wavelength rather than by a half wavelength. Furthermore, when the Fermi energy coincides with the second subband minimum, the transmission approaches unity for scatterer separations larger than a few wavelengths and is therefore no longer a periodic function of distance between scatterers.