CLASSE Student Seminar

Arthur Campello, Cornell University

Abstract: 

Diamond crystals serve a wide array of technological applications, including as candidate materials for qubits, for high power electronics, as high-power radiation windows for optics, and many others. Quantitative characterization of crystal defects is crucial for development of the applications and for further advancements in materials science.

Currently, few options exist for direct measurement/mapping of lattice strain in the bulk of the crystal under in-situ conditions. With a commonly used technique, white-beam x-ray topography, nature of some lattice defects can be revealed and their strain features can be determined either qualitatively or semi-quantitatively. Pairing inferences from white-beam topographs with a novel diffraction microscopy approach, involving near-backscattering diffraction, we can produce quantitative strain dilation maps with ~ 1x10^{-8} strain resolution to further quantify underlying imperfections. We report verifying the validity of this method by comparing measured strains with those predicted by the linear theory of elasticity. Additionally, we have mapped the strain field of a previously unobserved dislocation type in diamond, a predominately screw type with a dislocation line direction close to [001].