1ST-PRINCIPLES CALCULATIONS OF ELECTRONIC SUBBAND STRUCTURE AND ELEMENTARY EXCITATIONS OF A QUANTUM WIRE

Self-consistent calculations of the subband electronic structure of semiconductor quantum wires are reported. The Schrodinger and Poisson equations were solved simultaneously in a rectangular waveguide geometry, using Fermi statistics for electrons at finite temperature. Calculated energy levels, wave functions. charge density, and potential differ from the predictions of the simple square well and harmonic oscillator models because of the influence of accumulation and depletion regions. The subband energies depend on the free-carrier density and the temperature as well as the band bending. Based on the self-consistently determined subband structure, the dynamical structure factor was evaluated using a nonlocal description of dielectric response theory in the random-phase approximation at finite temperature. We obtain intersubband as well as intrasubband plasmons and discuss their dispersion relations, localization, and line shapes. The dynamical structure factor of our model quasi-one-dimensional electron gas displays unique line shapes and dispersion relations which are in sharp contrast with the results expected for higher-dimensional electron gas.