Chaos, interactions, and nonequilibrium effects in the tunneling resonance spectra of small metallic particles

TL;DR

This paper explains the clustering observed in tunneling resonance spectra of small metallic particles by linking it to excited single-electron states and nonequilibrium effects, assuming chaotic classical electron dynamics.

Contribution

It introduces a model connecting resonance clusters to excited states and nonequilibrium occupancy, with a quantitative estimate of the typical energy shift based on classical chaos assumptions.

Findings

Clusters correspond to excited single-electron states.

Energy shifts are proportional to the inverse of the conductance.

Chaotic dynamics underpin the spectral features.

Abstract

We explain the observation of clusters in the tunneling resonance spectra of small metallic particles of few nanometer size. Each cluster of resonances is identified with one excited single--electron state of the metal particle, shifted as a result of the different nonequilibrium occupancy configurations of the other single--electron states. Assuming the underlying classical dynamics of the electrons to be chaotic, we determine the typical shift to be $\Delta/g$ where $g$ is the dimensionless conductance of the grain.