Related Experiment Video
Updated: Aug 15, 2026

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures
Published on: October 9, 2012
Observation of discrete energy levels in a quantum confined system
L L A Adams1, B W Lang, A M Goldman
1School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, Minnesota 55455, USA.
Abstract:
Low temperature scanning tunneling microscope images and spectroscopic data have been obtained on subnanometer size Pb clusters fabricated using the technique of buffer layer assisted growth. Discrete energy levels were resolved in current-voltage characteristics as current peaks rather than current steps. Distributions of peak voltage spacings and peak current heights were consistent with Wigner-Dyson and Porter-Thomas distributions, respectively, suggesting the relevance of random matrix theory to the description of the electronic eigenstates of the clusters. The observation of peaks rather than steps in the current-voltage characteristics is attributed to a resonant tunneling process involving the discrete energy levels of the cluster, the tip, and the states at the interface between the cluster and the substrate surface.
Related Concept Videos
The Bohr Model
Emission Spectra
The de Broglie Wavelength
The Quantum-Mechanical Model of an Atom
Molecular Spectroscopy: Absorption and Emission
Energy Bands in Solids
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states that no two...

