STEM image simulation by Bloch-wave method with layer-by-layer representation

In a Bloch-wave-based STEM image simulation, a framework for calculating the cross section for any incoherent scattering process was formulated by Allen et al. [(2003) Lattice-resolution contrast from a focused coherent electron probe. Part I. Ultramicroscopy 96: 47-63; Part II. ibid. 96: 65-81]. They simulated the high-angle annular dark-field, back-scattered electron, electron energy-loss spectroscopy and energy-dispersive X-ray (EDX) STEM images from the inelastic scattering coefficients. Furthermore, a skilful approach for deriving the excitation amplitude and block diagonalization in the eigenvalue equation was employed to reduce computing time and memory. In the present work, I extended their scheme to a layer-by-layer representation for application to inhomogeneous crystals. Calculations for a multi-layer Si sample including a displaced layer were performed by multiplying Allen et al.'s block-diagonalized matrices. Electron intensities within the sample and EDX STEM images were calculated at various conditions. From the calculations, three-dimensional STEM analysis was considered.