Statistics of Coulomb Blockade Peak Spacings

Abstract

Distributions of Coulomb blockade peak spacings are reported for large ensembles of both unbroken (magnetic field $B=0\mathrm{}$) and broken ( $B\ne 0$) time-reversal symmetry in GaAs quantum dots. Both distributions are symmetric and roughly Gaussian with a width of $\sim 2\%–6\%$ of the average spacing, with broad, non-Gaussian tails. The distribution is systematically wider at $B=0\mathrm{}$ by a factor of $\sim 1.2\pm 0.1$. 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.