THE EFFECT OF MODE-COUPLING ON BALLISTIC ELECTRON-TRANSPORT IN QUANTUM WIRES

Ballistic electron transport in arbitrarily shaped wires is modelled by the conversion processes of elementary quantum modes. The resistance quantization and geometrical resonances are calculated in cavity structure embedded in a quantum wire. At the resonant points, which correspond to virtual bound states, mode coupling becomes essential and the propagation of one mode is enhanced and blocked by the virtual bound state of the other, resulting in the appearance of a pair of resonant and anti-resonant peaks. The phase shift of the scattering matrix is shown to be a powerful indicator for analysing the coupling among quantum modes.