STATISTICS OF CONDUCTANCE OSCILLATIONS OF A QUANTUM-DOT IN THE COULOMB-BLOCKADE REGIME

The fluctuations and the distribution of the conductance peak spacings of a quantum dot in the Coulomb-blockade regime are studied and compa red with the predictions of random matrix theory (RMT). The experiment al data were obtained in transport measurements performed on a semicon ductor quantum dot fabricated in a GaAs-AlGaAs heterostructure. It is found that the fluctuations in the peak spacings are considerably larg er than the mean level spacing in the quantum dot. The distribution of the spacings appears to be Gaussian both for zero and for non-zero ma gnetic field and deviates strongly from the RMT predictions.