  The electronic properties of single and few-particles in core-shell nanowire
quantum dots (NWQD) are investigated. By performing configuration interaction
(CI) calculations we particularly elucidate how elevated symmetry character
(C3v or D2d) exhibited by single particle orbitals enhances the phase coherence
of exciton-photon wavefunction though suppressing spin flip processes. Detailed
calculations presented here demonstrate how strain-induced potentials
manipulate the symmetry characters, intrinsic oscillator strength and
electron-hole dipole in NWQDs. An orbital-dependent kinetic energy is defined
based on single particle dispersion and orbital spreadout in k-space. It is
shown the exchange occurring between this kinetic energy and strain-induced
potentials is responsible for orbital distortions, and thus the energy
reordering of different direct and correlation terms. Various structures have
been examined to elaborate on the influence of size and orientation together
with axial and lateral symmetry of NWQDs. Our many-body calculations suggest
that binding energies of s-shell few particle resonances XX0 and trions are
suppressed when axial and lateral localizations become comparable. Then
exerting an external perturbation may renormalize the binding energies,
realizing a transition from anti-binding to binding regime or reverse. In this
regard, we specifically show that kinetic energy of single particles, and thus
correlation energies of associated complexes, exposed to an electric field
remain relatively unaffected and the interplay between direct Coulomb terms
reorders the multiexcitonic resonances. Sub-micro-eV fine structure splitting
along with the tunable XX0 binding energy offers NWQDs promising for generating
entangled photons in both regular and time reordering schemes.
