Electronic Coupling of Quantum-Well States in Double Ag Nanofilm Structures

Abstract

We have carried out an angle-resolved photoemission study of double Ag nanofilm structures, composed of an outer Ag nanofilm/Cu barrier layer/inner Ag nanofilm/Cu(111) substrate, in order to investigate the electronic coupling between the quantum-well (QW) states. It is found that the eigenvalues of coupled QW states in the present double Ag nanofilm structures show the avoided-crossing behavior, indicative of the electronic coupling between the QW states through a thin Cu barrier layer. Furthermore, it is found that electronic coupling strength decreases with increasing the Cu barrier layer and inner Ag nanofilm thickness. We have compared these experimental results with the theoretical calculations based on the nearly-free-electron approximation. From these results, we discuss the electronic coupling between the QW states in the double Ag nanofilm structures with various configurations.