Avoided crossings of Au(111)/Ag/Au/Ag double-quantum-well states

A ${\mathrm{Ag}}_8$/${\mathrm{Au}}_3$/${\mathrm{Ag}}_{\mathit{x}}$ double quantum well is grown on Au(111) to form two Ag quantum wells coupled through a thin Au barrier layer, and the electronic structure of this system is examined with angle-resolved photemission. As the thickness of the outer well (x, in monolayers) is varied, the measured binding energies of the quantum-well states show an avoided-crossing behavior, in good agreement with a model calculation based on Bloch wave functions. The results demonstrate the effect of electronic translayer coupling.