A new aberration-corrected, energy-filtered LEEM/PEEM instrument II. Operation and results

In Part I we described a new design for an aberration-corrected Low Energy Electron Microscope (LEEM) and Photo Electron Emission Microscope (PEEM) equipped with an in-line electron energy filter. The chromatic and spherical aberrations of the objective lens are corrected with an electrostatic electron mirror that provides independent control of the chromatic and spherical aberration coefficients Cc and C3, as well as the mirror focal length. In this Part II we discuss details of microscope operation, how the microscope is set up in a systematic fashion, and we present typical results.

► The Cc and C3 aberrations of a LEEM/PEEM instrument are corrected with an electrostatic electron mirror.
► The mirror provides independent control over Cc, C3 and focal length in close agreement with theory.
► A detailed alignment procedure for the corrected microscope is given.
► Novel methods to measure Cc and C3 of the objective lens and the mirror are presented.
► We demonstrate a record spatial resolution of 2 nm.