Mapping the Local Density of States by Very-Low-Energy Scanning Electron Microscope

Reflection of very slow electrons from solid surfaces has been reported to be inversely proportional to the local density of electronic states coupled to the incident electron wave. The reflected electron flux at units of eV used as the image signal in a scanning electron microscope allows mapping of the local density of states at high spatial resolution. Good performance of the microscope at very low energies is enabled by introducing the beam-retarding immersion lens (the cathode lens) with a biased specimen serving as the cathode. Results of demonstration experiments on aluminum are provided. [doi:10.2320/matertrans.MC200921]