Ground state energy fluctuations of interacting electrons in disordered quantum dots

The distribution of the peak spacings of Coulomb oscillation is theoretically investigated in disordered quantum dots. Taking account of the electron-electron interaction by the perturbation, we show that a pair-type (BCS-type) correlation plays an important role in determining the distribution, which could deviate drastically from the prediction of the random matrix theory. A possible mechanism of a sharp peak structure is proposed, which is in accordance with numerical results.