Signatures of spin pairing in a quantum dot in the Coulomb blockade   regime
  Coulomb blockade resonances are measured in a GaAs quantum dot in which both shape deformations and interactions are small. The parametric evolution of the Coulomb blockade peaks shows a pronounced pair correlation in both position and amplitude, which is interpreted as spin pairing. As a consequence, the nearest-neighbor distribution of peak spacings can be well approximated by a smeared bimodal Wigner surmise, provided that interactions which go beyond the constant interaction model are taken into account. 
S. Luescher, T. Heinzel, K. Ensslin, W. Wegscheider, and M. Bichler