Off gap interface reflectivity of electron waves in Fabry Perot resonators

The interface reflectivity in the MgW(110) metallic quantum well is from line shape analysis of high resolution photo emission. A quick reflectivity drop is found away from projected band of the appropriate symmetry near Ef, such that the interface overcomes the bulk like quasi particle lifetime as the line broadening mechanism. A nearly free electron model for the W(110) substrate band structure demonstrates coherent wave function scattering is the relevant mechanism determines the interface reflectivity in the resonator.