Showing papers by "David Broido published in 1992"
TL;DR: In this paper, the authors derived the Hamiltonian which describes in second quantization the interaction of quantum-well excitons with photons and obtained by solving the corresponding quantum-mechanical equations of motion the dispersion relations for localized and resonant polaritons as well as the lifetime for the resonant modes.
9 citations
TL;DR: Inelastic light scattering is used to study the collective charge- and spin-density excitations associated with electronic intersubband transitions in GaSb-AlSb superlattices and shows that the nonparabolicity of the conduction band must be properly included in order to yield quantitative agreement.
Abstract: We have used inelastic light scattering to study the collective charge- and spin-density excitations associated with electronic intersubband transitions in GaSb-AlSb superlattices. The density of the photoexcited two-dimensional electron-hole plasma was controlled by varying the incident laser power. A comparison of experiment with detailed calculations of the response functions shows that the noparabolicity of the conduction band must be properly included in order to yield quantitative agreement. It is found that nonparabolicity, in addition to decreasing the resonance energies of the collective excitations, provides a mechanism for observing single-particle excitations at q=0.
8 citations
TL;DR: The single-particle spectrum of holes in parabolic quantum dots in a magnetic field is investigated and it is noted that the band mixing causes Kohn's theorem to be violated, allowing for a richer far-infrared optical response.
Abstract: The single-particle spectrum of holes in parabolic quantum dots in a magnetic field is investigated. The calculted Landau-level structure and allowed transition-energy spectrum for the heavy and light holes is considerably more complicated than that obtained for quantum dots containing electrons. This is because of the valence-band mixing, which produces strong anticrossings of the Landau levels and substantial wave-function mixing. It is noted that the band mixing causes Kohn's theorem to be violated, thus allowing for a richer far-infrared optical response.
5 citations
TL;DR: In this paper, the charge-density and spin-density intersubband transitions of electrons in [100] and [111] GaSb/AlSb multiple quantum wells have been measured with inelastic light scattering.
1 citations
01 Jan 1992
TL;DR: In this article, the authors considered deviations in the kinetic energy part (band structure effects) to demonstrate modifications in the energy level spectrum and in the dipole excitation spectrum and presented theoretical results for a system, which has not yet been investigated experimentally.
Abstract: Quantum dots, realized by imposing lateral structure on a 2-dimensional electron system, have been described so far mainly by the concepts of the two-dimensional isotropic harmonic oscillator. Single particle excitation energies seem to dominate the spectrum. With the advent of improved technology experimental data indicate the necessity to refine this model. We consider deviations in the kinetic energy part (band structure effects) to demonstrate modifications in the energy level spectrum and in the dipole excitation spectrum. As a particular case we present theoretical results for a system, which has not yet been investigated experimentally: quantum dots with holes.
1 citations