This dataset allows to investigate phase contrast methods for 4D scanning transmission electron microscopy, such as ptychography.

A synthetic dataset has been simulated, based on an SrTiO₃ unit cell as a starting point. Then, a five by five super cell was created by repetition. Two artificial spatial frequencies were added to the phase grating, one with a wavelength of a single unit cell and one with a wavelength of the super cell. To eliminate dynamical scattering, a 4D-STEM simulation with 20 × 20 scan points per unit cell was performed using only one slice with a thickness of one unit cell along electron beam direction [001].

Files

• conf_01.mat: HDF5 file with the phase grating.
• Data extraction and plot of the phase grating.ipynb: Jupyter notebook showing how to access the phase grating file and plot the data.
• slice_00001_thick_1.9525_nm_blocksz100.raw: Simulated 4D STEM dataset as a raw binary file. Shape 100 x 100 x 596 x 596, dtype float32.
• ssb-example.ipynb: Jupyter notebook showing first moment analysis and ptychography with the dataset.

Simulation parameters

• Scan points: 100x100
• Field of view: 1.9525nm
• Convergence angle: 23mrad, 136 px
• Acceleration voltage: 300 kV
• Center: (297, 297)
• Rotation angle: 0°