Prediction of inelastic light scattering spectra from electronic collective excitations in GaAs/AlGaAs core-multishell nanowires

Abstract

We predict inelastic light scattering spectra from electron collective excitations in a coaxial quantum well embedded in a core-multishell GaAs/AlGaAs nanowire. The complex composition, the hexagonal cross section, and the remote doping of typical samples are explicitly included, and the free electron gas is obtained by a density functional theory (DFT) approach. Inelastic light scattering cross sections due to charge and spin collective excitations belonging to quasi-one-dimensional (1D) and quasi-2D states, which coexist in such radial heterostructures, are predicted in the nonresonant approximation from a fully three-dimensional multisubband time-dependent DFT (TDDFT) formalism. We show that collective excitations can be classified in azimuthal, radial, and longitudinal excitations, according to the associated density fluctuations, and we suggest that their character can be exposed by specific spectral dispersion of inelastic light scattering along different planes of the heterostructure.

Band structure of n- and p-doped core-shell nanowires

“…Due to comparable kinetic and Coulomb energies, in doped core-shell nanowires (CSNWs) electronic states [18] and ensuing response functions [19,20] are determined by the self-consistent field of free carriers, which, in turn depends on the concentration and type of doping [18], together with the Fermi level pinning at surface states [21,22]. Hence, different doping regimes may result in distinct charge localization patterns [23].…”

Exact long-wavelength plasmon dispersion on a ring with soft Coulomb interactions

“…Indeed, collective modes of free electrons at the surface easily couple to the light field matching the proper frequency of the charge plasma, enhancing, e.g, the performance of LED [4] and light-harvesting [5] devices. The specific interest in plasmonic modes with a 1D character [6][7][8][9] arises from their simple and robust dispersion relation. 1D plasmon modes are supported in quasi-1D metallic ultrathin nanowires with diameter of few tens of nanometres, which can now be grown with highly controllable geometry [10], but 1D modes with circular symmetry are also supported at the edges of metallic nanodiscs [11] or confined in nanorings [12].…”