Ballistic transport of electrons in T-shaped quantum waveguides

Ballistic transport of electrons through T-shaped quantum waveguides with stubs of small lithographic area (0.075 mu m(2)) has been studied. Measurements of the conductance G at 90 mK as a function of the top gate voltage, which changes the stub height, show well-defined, almost periodic oscillations in G. A theoretical analysis, involving estimation of the shape and size of the device under gate biases and computation of the transmission probabilities from numerical analysis of the Schrodinger equation, successfully explains the main features of the experimental observations. The observed minima in G can be attributed to reflection resonances of electron waves from the resonant states of the stub cavity. This work establishes the potential of electron stub tuners in microelectronics applications. (C) 1999 American Institute of Physics. [S0003-6951(99)00605-1].