Dipole spectra of holes in quantum dots

Abstract

The eigenenergies and the dipole excitation spectrum of a single hole in a quantum dot is calculated as a function of a magnetic field. To describe a realistic dot based on an ${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As/GaAs heterostructure we use a triangular subband potential and a parabolic lateral confinement. The bulk valence band structure is considered by using the Luttinger Hamiltonian. In the absence of band mixing, the parabolic confinement would lead to only two dipole transitions, with the well known resonance frequencies previously established for dots containing electrons. The strong coupling of light- and heavy-hole states leads to a substantial shift of these resonance frequencies and introduces new features at transition energies comparable to the heavy-hole--light-hole subband separation.