Role of Inelastic Tunneling through the Barrier in Scanning Tunneling Microscope Experiments on Cuprates

摘要

The tunneling path between the CuO2-layers in cuprate superconductors and ascanning tunneling microscope tip passes through a barrier made from otheroxide layers. This opens up the possibility that inelastic processes in thebarrier contribute to the tunneling spectra. Such processes cause one orpossibly more peaks in the second derivative current-voltage spectra displacedby phonon energies from the density of states singularity associated withsuperconductivity. Calculations of inelastic processes generated by apicalO-phonons show good qualitative agreement with recent experiments reported byLee et al.[1]. Further tests to discriminate between these inelastic processesand coupling to planar phonons are proposed.