Towards 2D Strain Mapping in Quantum Materials via Multi-Peak Bragg Ptychography

Understanding and controlling strain in thin crystalline membranes is critical for quantum technologies, as strain and defects can strongly alter the electronic and optical properties of embedded quantum defects such as NV⁻ centers in diamond or divacancies in SiC. Freestanding membranes with engineered defects are promising candidates for integration into functional devices. Accessing multiple non-colinear Bragg reflections enables measurements of independent projections of the displacement field along different scattering vectors, forming the basis for multi-peak Bragg ptychography (MPBP), a method capable of reconstructing the full 2D displacement field. We present Bragg ptychography measurements sensitive to multiple projections of a single dislocation in a 150 nm-thick Si membrane, obtained from the (111), (11-1), and (040) reflections at MAX IV. These results represent a key step toward MPBP as a quantitative, high strain-sensitivity method for strain mapping in thin membranes. While demonstrated on Si, this approach is directly applicable to quantum materials where precise strain characterization is essential for optimizing coherence and optical properties.