High-resolution imaging of inhomogeneities in superconducting tunnel junctions by scanning with a modulated electron beam

A two-dimensional image of spatial structures within a superconducting tunnel junction can be obtained by scanning the current-biased junction with an electron beam and detecting the voltage change. The resolution of this imaging technique is governed by the thermal-healing length which describes the spatial diffusion of the beam energy through the superconducting film. Due to the thermal skin efect this resolution can be improved remarkably by high-freqency modulation of the beam intensity and synchronous signal detection. © 1983.