BALLISTIC ELECTRON TRANSMISSION IN COUPLED PARALLEL WAVE-GUIDES

Four-terminal resistances in parallel electron-waveguide structures coupled by a window region are calculated using classical- and quantum-mechanical methods. An electron incident through one of the waveguides can travel into the other in the quantum ballistic regime. The transmission coefficients into the ends of the second waveguide oscillate as one of the sample parameters, such as the separation between the waveguides or the Fermi energy, is varied, leading to quasiregular modulations in the transfer resistance. Several different mechanisms ale responsible for the oscillations including (i) classical specular reflections from the side wall of the window region, (ii) depopulation of quasi-one-dimensional subbands in the waveguides, and (iii) Fabry-Perot-type quantum interference in the window region. We propose that these scenarios of the oscillations can be distinguished experimentally by their peculiar dependence on the system parameters.