Simple spin textures in a quantum dot

Measurements and calculations previously reported for a lateral quantum dot at magnetic fields close to the transition to the maximum density droplet provided evidence that the increase of spin polarisation of a dot with magnetic field is interrupted by spin depolarization events. The loss of spin polarisation is associated with correlated states corresponding to condensation of spin excitons into spin textures. In this paper a detailed experimental and theoretical analysis is performed of the excitation spectra at the first two spin flip events in a few electron quantum dot. In this less complicated regime we are able to identify these correlated states as spin and charge excitons and bi-excitons. In particular we focus on a dot containing eight electrons. Coulomb blockade experiments, supported by detailed calculations, confirm the presence of these correlated states at the second spin flip.