Statistics of conductance oscillations of a quantum dot in the Coulomb-blockade regime

TL;DR

This paper investigates the fluctuations and distribution of conductance peak spacings in a quantum dot within the Coulomb-blockade regime, revealing deviations from random matrix theory predictions through experimental measurements.

Contribution

It provides experimental data on conductance fluctuations in quantum dots and compares these with theoretical RMT predictions, highlighting significant discrepancies.

Findings

Fluctuations in peak spacings are larger than the mean level spacing.

Distribution of spacings appears Gaussian under various magnetic fields.

Deviations from RMT predictions are observed in experimental data.

Abstract

The fluctuations and the distribution of the conductance peak spacings of a quantum dot in the Coulomb-blockade regime are studied and compared with the predictions of random matrix theory (RMT). The experimental data were obtained in transport measurements performed on a semiconductor quantum dot fabricated in a GaAs-AlGaAs heterostructure. It is found that the fluctuations in the peak spacings are considerably larger than the mean level spacing in the quantum dot. The distribution of the spacings appears Gaussian both for zero and for non-zero magnetic field and deviates strongly from the RMT-predictions.