Retrieving the energy band of Cu thin films using quantum well states

Abstract

Angle-resolved photoemission electron spectroscopy (ARPES) measurement was performedon epitaxially grown Cu/Co/Cu(001) films to observe the quantum well (QW) states dueto the electron confinement inside the Cu film by the Cu/Co and Cu/vacuum interfaces. Bystudying the in-plane dispersion of the QW states, we find a nearly isotropic electronicstructure in the neck region of the Fermi surface. Based on the quantization condition, weachieve a model-free method for obtaining the copper energy band and the energy contour near the Fermi energy. The result is in good agreement withtheoretical calculations of the bulk copper energy band, showing that there is no significantdifference in the energy bands between the bulk and thin film copper. This method can begeneralized to measure energy bands of other metallic films using the QW states.