Signatures of Random Matrix Theory in the Discrete Energy Spectra of Subnanosize Metallic Clusters

Abstract

Lead clusters deposited on Si(111) substrates have been studied at low temperatures using scanning tunneling microscopy and spectroscopy. The current-voltage characteristics exhibit current peaks that are irregularly spaced and varied in height. The statistics of the distribution of peak heights and spacings are in agreement with random matrix theory for several clusters. The distributions have also been studied as a function of cluster shape.Comment: 10 pages, 9 figures, to appear in Phys. Rev.