The energy dependence of the tunneling coefficient for a cylindrical semiconductor nanowire, i.e., a one-dimensional electron gas, with two constrictions is studied. Using the R-matrix formalism the localization probabilities at the resonant energies can be computed. They give decisive information about the physical meaning of the resonant peaks and dips that appear. The nanowire with two constrictions yields a well-defined system for the experimental evidence of the quasi-bound states of the evanescent channels. Clearly marked dips due to them should appear in the linear conductance at low temperatures.
Tunneling coefficient for a cylindrical nanowire with one or two constrictions, for a specific magnetic quantum number m. The influences of the geometrical parameters on the resonant energies are also shown.