• inner-shell excitation;
  • secondary electron;
  • atomic resolution;
  • quantum Monte Carlo

It has been experimentally achieved atomic resolution imaging by using secondary electron (SE) signals in a scanning transmission electron microscope with aberration correction. The underlying physical mechanism needs to be understood and has attracted considerable theoretical interest. Several recent calculations taking account of the inner-shell ionization for high-energy SE production have not included the cascade production of low-energy SE signals which was believed to destroy the local information in SE imaging. In this work, we have developed a new theoretical method, a quantum Monte Carlo simulation, to calculate atomic resolution SE image by including every physical factor in SE generation, transportation and emission for a crystalline solid. This quantum Monte Carlo simulation method combines the Bohmian quantum trajectory method for treating electron elastic scattering and diffraction in a crystal with a conventional Monte Carlo sampling of inelastic scattering events along quantum trajectory paths. Simulation of atomic resolution SE image for atom columns in a copper crystal is performed. The contribution of the inner-shell excitation to atomic resolution SE imaging is studied. Copyright © 2014 John Wiley & Sons, Ltd.