Selected energy dark-field imaging using low energy electrons for optimal surface phase discrimination

We propose a general strategy for surface phase discrimination by dark-field imaging using low energy electrons, which maximizes contrast using diffraction spots, at selected optimal energies. The method can be automated to produce composite phase maps in real space and study the dynamics of complex phase transformations in real-time. To illustrate the capabilities of the technique, surface phases are mapped in the vicinity of liquid Ga droplets on the technologically important GaAs (001) surface. The data is in .dat format, each file corresponds with a photogram of a movie taken with the Low Energy Electron Microscope. 3 types of data can be found: Photograms from Low Energy Electron Diffraction profiles. In this cases the x/y plane corresponds to coordinates in the reciprocal space taken at given electron energies. Photograms from real space movies taken with the Low Energy Electron Microscope at given electron energies. In this case the x/y plane corresponds to real space coordinates, where the total size of the image varies between 20 microns and 6 microns. Each file is labelled a,b,c,d depending on the diffracted beam we are selecting, being a.diffracted beam from c(8x2), b. diffracted beam from 6x6 pattern, c. diffracted beam from 3x6 pattern, d. diffracted beam from 2x4 pattern. IV curves: Data extracted from the total intensity of a particular diffracted beam of a certain pattern. The Y axis represents the total intensity, and the X-axis represents the energy.