Fluctuation transmission electron microscopy (FTEM) is an experimental technique for identifying configurational order in glassy materials which are otherwise difficult to distinguish by conventional diffraction techniques or measurements, such as the pair distribution function. Having
the capability to accurately simulate an FTEM measurement, including microscope parameters and model size, enables a quantitative association between models and experiments for glassy materials.
A parallelized software package has been produced by the authors which mimics transmission electron microscope (TEM) parameters, including beam defocus, beam convergence, third and fifth order spherical aberration, and the finite pixel size of the microscope detector. The software uses the multislice method to enable accurate simulation of sample thicknesses comparable to those examined in experiment, e.g. 30 nm. The FTEM software has also been coupled to molecular dynamics software to incorporate effects of atomic motion in a glassy material. By producing greater accuracy in simulating this experimental measurement, we enable greater confidence in identifying candidate models of atomic configurations for glassy materials.
Authors: Nick Julian and Jaime Marian