HRTEM / STEM Simulator¶

The HRTEM/STEM Simulator simulates TEM lattice-fringe (HRTEM) images, STEM images, and projected potentials. Click Simulate to run.

Keyboard & mouse shortcuts¶

Results are shown as one or more image panes. They use ReciPro's standard image-view navigation, and all panes pan and zoom together.

Shortcut	Action
`F1`	Open this page of the online manual
`CTRL`+`C` (image grid focused)	Copy the image(s) to the clipboard as a metafile
Left-drag / Middle-drag	Pan the image (all panes move together)
Mouse wheel up / down	Zoom in (×2) / out (×0.5) at the cursor
Right-drag a box	Zoom in to the selected region
Right-click / Right double-click	Zoom out (×0.5)
`CTRL` + Right-drag a box	Select a rectangular area
Left double-click a pane	Maximise that pane / restore the grid (multi-pane layouts)
Move the mouse (no button)	Read the position (pm) and pixel value at the cursor

→ See 21. Keyboard & mouse shortcuts for every window at a glance.

Quick Routes by Goal¶

Goal	Start from	Reference
Calculate one HRTEM image	Set Image mode to HRTEM, then set accelerating voltage and defocus in TEM conditions	HRTEM simulation, HRTEM image formation
Calculate a STEM image	Set Image mode to STEM, then set convergence angle and detector in STEM options	STEM simulation, STEM calculation
View projected potential	Set Image mode to Potential	Potential simulation
Generate a thickness / defocus series	Configure Single / Serial and the image conditions in HRTEM options	HRTEM simulation
Use HAADF-STEM with TDS	Set non-zero atomic temperature factors and use an LAADF / HAADF detector	STEM calculation

Basic Workflow¶

Select the crystal and orientation in the main window, then open this simulator.
Choose HRTEM, STEM, or Potential in Image mode.
Set accelerating voltage, defocus, aberrations, apertures, and STEM convergence settings in Optical property.
Set thickness, image size, resolution, Bloch-wave count, and partial-coherence model in Simulation property.
Click Simulate, then adjust brightness, normalisation, scale bar, and labels in Display settings.

Image area¶

The left half of the window shows the simulated image. The status bar across the top reports the cursor position (X:, Y:) and the image Value: (intensity) under the cursor, next to a Low → High intensity scale that reflects the current colour map and brightness range.

Image mode / Sample¶

HRTEM, Potential, or STEM.

Sets the sample thickness.

Optical property¶

TEM conditions¶

Acc. voltage, defocus (Scherzer shown).

Acc. voltage¶

Accelerating voltage of the electron microscope. Changing this updates the relativistically-corrected wavelength (displayed beside the field) and, together with Cs, the suggested Scherzer defocus value shown below.

Defocus¶

Defocus value of the objective lens. The Scherzer defocus (the value that maximises the phase-contrast transfer in the weak-phase-object approximation) is shown below as a reference.

Inherent property (HRTEM optical aberrations)¶

Microscope-specific aberration parameters used by the lens-function calculation.

Cs — spherical aberration coefficient.
Cc — chromatic aberration coefficient.
β — illumination semi-angle (finite-source effect).
ΔE — 1/e width of the electron-energy fluctuation.

Lens function¶

Plots of the lens function. Adjusting the upper limit of u changes the drawing range.

sin[χ(u)] — phase-contrast transfer function (PCTF).
E_s(u) — spatial-coherence envelope function.
E_c(u) — temporal-coherence envelope function.

Objective aperture (HRTEM option)¶

Cs, Cc, beta, delta-E, PCTF, spatial/temporal coherence envelopes, objective aperture.

Size¶

Objective aperture size in mrad. Tick Open aperture to remove the aperture. The number of diffraction spots taken into the Bloch-wave calculation depends on the aperture; the maximum is bounded by the Max Bloch waves value in Simulation property.

Shift¶

Horizontal displacement of the aperture in mrad — used to mimic an offset objective aperture in HRTEM.

Spot info¶

Opens the detailed spot list (intensity, complex amplitude, etc.) for the reflections passing through the aperture. Convenient when the Diffraction Simulator is also open for comparison.

STEM options (optical)¶

Convergence semi-angle¶

Half-angle of the convergent probe (mrad). Controls the size of the STEM probe and the spatial resolution of the simulated image.

Detector geometry¶

Inner / outer collection angles of the annular detector (mrad). Choose between BF (small inner angle), ABF, LAADF, HAADF (large inner angle).

Scan area / step¶

Scan field of view and pixel size for the STEM image.

Simulation property¶

HRTEM options¶

Max Bloch waves, image pixels/resolution, partial coherence (quasi-coherent / TCC), Single/Serial mode.

Max Bloch waves¶

Maximum number of Bloch waves used in the dynamical calculation. Increasing this improves accuracy at the cost of O(N³) eigenvalue solving time.

Image property (pixels & resolution)¶

Pixel dimensions and sampling resolution of the simulated image. Higher resolution gives a finer fringe pattern but proportionally longer FFT time per slice.

Partial-coherent model¶

How wave interference is treated when combining the contributions from all incident-beam directions.

Quasi-coherent — fast, approximate model that multiplies the phase-contrast transfer function by spatial- and temporal-coherence envelopes.
Transmission cross coefficient (TCC) — more accurate model that integrates over the full transmission cross coefficient. Slower but exact in the linear-imaging regime.

See Appendix A3.2 — HRTEM image formation.

Single / Serial mode¶

Single image — simulates a single image at the thickness set in Sample property and the defocus set in Optical property.
Serial image — generates a thickness × defocus matrix according to Start / Step / Num for each. Useful for finding the best matching condition against an experimental image.

STEM options (simulation)¶

Bloch wave count — same role as for HRTEM, applied per probe position.
Angular resolution — number of sample points in the probe-direction integration.
TDS treatment — whether to include thermal-diffuse scattering via temperature factors B. Required for LAADF/HAADF.