Statistics of Coulomb Blockade Peak Spacings

TL;DR

This paper reports on the statistical distributions of Coulomb blockade peak spacings in GaAs quantum dots under different magnetic field conditions, revealing symmetry, width variations, and absence of certain correlations.

Contribution

It provides the first comprehensive analysis of peak spacing distributions for large ensembles of quantum dots with and without broken time reversal symmetry.

Findings

Distributions are symmetric and roughly Gaussian with broad tails.

Peak spacing distribution is wider at zero magnetic field.

No evidence of spin-degeneracy or correlation with peak height.

Abstract

Distributions of Coulomb blockade peak spacing are reported for large ensembles of both unbroken (magnetic field B = 0) and broken (B <> 0) time reversal symmetry in GaAs quantum dots. Both distributions are symmetric and roughly gaussian with a width ~ 2-6% of the average spacing, with broad, non-gaussian tails. The distribution is systematically wider at B = 0 by a factor of ~ 1.2 +- 0.1. No even-odd spacing correlations or bimodal structure in the spacing distribution is found, suggesting an absence of spin-degeneracy. There is no observed correlation between peak spacing and peak height.