In the technique of Electron Backscatter Diffraction (EBSD), the accurate detection and identification of different phases existing in a sample is often limited by overlapping Kikuchi diffraction patterns originating from the extended probing volume of the individual EBSD map points measured in the scanning electron microscope (SEM). We present an iterative approach that uses simulated Kikuchi patterns to resolve several overlapping diffraction signals. For each measured EBSD pattern, our method first identifies the best-fit simulated Kikuchi pattern using dynamic template matching. This simulated, ideal reference pattern is then further processed to optimally match the experimental image, uncovering any underlying weaker signals after subtraction. Repeatedly utilizing dynamic template matching and pattern subtraction on residual signals of subsequent steps enables the identification of minor phases that might otherwise be missed from the probing volume of the EBSD map point. This method significantly improves phase detection in complex materials, addressing a key limitation of conventional EBSD analysis that conventionally assigns a single phase to each map point. The present method does not require a known orientation relationship between the phases of the overlapping patterns or close neighbor experimental patterns like previously published approaches.

The intricate fine structure of Kikuchi diffraction plays a vital role in probing phase transformations and strain distributions in functional materials, particularly in electron microscopy. Beyond these applications, it also proves essential in photoemission spectroscopy (PES) at high photon energies, aiding in the disentanglement of complex angle-resolved PES data and enabling emitter-site-specific studies. However, the detection and analysis of these rich faint structures in photoelectron diffraction, especially in the hard x-ray regime, remain highly challenging, with only a limited number of simulations successfully reproducing these patterns. The strong energy dependence of Kikuchi patterns further complicates their interpretation, necessitating advanced theoretical approaches. To enhance structural analysis, we present a comprehensive theoretical study of fine diffraction patterns and their evolution with energy by simulating core-level emissions from Ge(100) and Si(100). Using multiple-scattering theory and the fully relativistic one-step photoemission model, we simulate faint pattern networks for various core levels across different kinetic energies (106–4174 eV), avoiding cluster size convergence issues inherent in cluster-based methods. Broadening in patterns is discussed via the inelastic scattering treatment. For the first time, circular dichroism has been observed and successfully reproduced in the angular distribution of Si(100) 1s, revealing detailed features and asymmetries up to 31%. Notably, we successfully replicate experimental bulk and more “surface-sensitivity” diffraction features, further validating the robustness of our simulations. The results show remarkable agreement with the experimental data obtained using circularly polarized radiations, demonstrating the potential of this methodology for advancing high-energy PES investigations.

Abstract Shock-melt veins in ordinary chondrites record ultrafast, high-pressure mineral transformation reactions. However, resolving the nano- to microscale mineral assemblages that form and quench during these events remains challenging. Here we demonstrate that near-axis transmission Kikuchi diffraction (NA-TKD), combined with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), can reliably resolve crystal structures and Fe–Mg zoning in sub-micron, high-pressure olivine phases across 10–15 μm fields of view, providing new insights into shock transformation mechanisms. We apply this approach to shock-melt veins in the Catherwood L6 chondrite, where host olivine along the shock-vein margin transforms into dense, randomly oriented clusters of ringwoodite crystallites. These textures indicate rapid solid-state transformation by homogeneous intracrystalline nucleation and interface-controlled growth under strongly overstepped conditions. Olivine fragments entrained within the melt preserve similar ringwoodite-dominated cores but develop Fe-rich reaction zones and Mg-rich wadsleyite rims at melt-wetted grain boundaries, accompanied by interstitial majoritic garnet. These features record brief melt infiltration, partial dissolution, and melt-assisted recrystallization during shock events. Together, the observed microstructures define a two-stage, but spatially heterogeneous transformation sequence: initial solid-state ringwoodite formation followed by localized melt-mediated overprinting and wadsleyite crystallization. This demonstrates that pressure–temperature conditions vary substantially across a single shock-melt vein, allowing multiple transformation mechanisms to operate sequentially or simultaneously within the same system. By enabling phase discrimination, orientation mapping, and coupled chemical–structural analysis at ∼10–30 nm spatial resolution, NA-TKD combined with EDS provides nanoscale crystallographic mapping within the SEM. This approach allows shock transformation sequences to be reconstructed across micrometer-scale fields of view that are difficult to access using SEM and TEM alone, providing a powerful framework for interpreting high-pressure reaction pathways in planetary materials.

Transmission Kikuchi diffraction in the scanning electron microscope has gained popularity as a materials characterisation technique for its high throughput and nanometre-level spatial resolution. While conventional diffraction pattern analysis routines focus on Kikuchi bands on the diffraction patterns, the full physical picture of electron scattering and diffraction pattern formation is more complex. Analysis that accounts for additional diffraction features such as diffraction spots and excess-deficiency effects should provide more robust and accurate indexing, if they can be incorporated in pattern indexing or simulation routines. A more accurate understanding of their physics of formation and geometry is required to enable this change. In this work, we demonstrate geometric and full contrast dynamical simulation of on-axis transmission Kikuchi patterns, based on experimental patterns captured using a modular, direct electron detector-based set-up in the scanning electron microscope. First, a diffraction geometry calibration routine is proposed based on the electron channelling pattern of the direct electron detector. This allows us to accurately account for the position of diffraction spots in both geometric and dynamical simulations with good agreement with experimental patterns. Further, by introducing appropriate weight factors, simulation of incoherent diffuse intensity, and calculation of the energy spectra of diffracted electrons, simulated patterns can be obtained which accurately capture the many diffraction features on experimental patterns. Workflows and findings of this work can be used to improve pattern indexing routines, as well as the understanding of the physical processes in the formation of on-axis transmission Kikuchi patterns.

Electron backscatter diffraction (EBSD) in the scanning electron microscope is a powerful technique for the structural characterisation of crystalline materials. Recent advances in hardware and software have significantly improved the spatial resolution and sensitivity of orientation and strain of EBSD, enabling the detection of small misorientations, strain distributions and extended defects in nominally single crystal thin films. In this work, we demonstrate that EBSD can now resolve individual dislocations, identify their type and quantify relative local rotations and deviatoric strain associated with threading dislocations (TDs) in a GaN semiconductor thin film. By acquiring multiple EBSD datasets, we imaged approximately 2000 TDs and determined an average TD density of 8 & times; 108 cm-2. About 40 % were identified as edge TDs, with the remainder being pure screw or mixed TDs. For our interaction depth of approximate to 20 nm, the misorientation at a TD was on the order of a few mrad and the strain variation was approximately 1 & times; 10-3 (or 1 mm/m). Interpretation of these measurements were supported by isotropic elasticity simulations of rotations and strain due to TDs accounting for both bulk (infinite medium) and surface relaxation effects. These results establish EBSD as a viable method for direct imaging and quantitative analysis of dislocations in semiconductor thin films.

We present the application of electron backscatter diffraction (EBSD) as a technique for characterizing wurtzite (wz) and zincblende (zb) polytypes of GaN grown upon micropatterned Si (001) substrates. The Si substrate is etched to create parallel V-shaped grooves with opposing {111} facets before the deposition of GaN. EBSD revealed that wz-GaN growth fronts initially form on the {111} Si facets before undergoing a transition from a wurtzite to zincblende structure as the two growth fronts meet. Orientation analysis of the GaN structures revealed that the wz-GaN growth fronts had different growth orientations but shared the same crystallographic relationship with the zb-GaN such that ⊥{303¯8}wz∥⟨110⟩zb, ⟨112¯0⟩wz∥⟨110⟩zb, and ⊥{303¯4}wz∥⟨001⟩zb. Furthermore, the crystallographic relationship, {0001}wz-GaN∥{111}zb-GaN∥{111}Si, and alignment of the wz- and zb-GaN with respect to the Si substrate was investigated. The two wz-GaN ⟨0001⟩ growth directions were expected to coalesce at an angle of 109.5°; however, measurements revealed an angle of 108°. The resultant misalignment of 1.5° induces misorientation in the zb-GaN crystal lattice. While the degree of misorientation within the zb-GaN lattice is low, <1°, the zb-GaN lattice is deformed and bends toward the wz-GaN interfaces about the specimen direction parallel to the length of the V-groove. Further EBSD measurements over larger areas of the sample revealed that these results were consistent across the sample. However, it was also revealed that additional factors induce changes in the orientation of the zb-GaN lattice, which may relate to the initial growth conditions of the zb-GaN.

We summarize a data analysis approach for electron backscatter diffraction (EBSD) which uses high-resolution Kikuchi pattern simulations to measure isochoric relative deformation gradient tensors from experimentally measured Kikuchi patterns of relatively low resolution. Simulation-based supersampling of the theoretical test diffraction patterns enables a significant precision improvement of tensor parameters obtained in best-fit determinations of strains and orientations from low-resolution experimental patterns. As an application, we demonstrate high-resolution orientation and strain analysis for the model case of hardness test indents on a Si(100) wafer, using Kikuchi patterns of variable resolution. The approach shows noise levels near 1 × 10^-4 in the relative deviatoric strain norm and in the relative rotation angles on nominally strain-free regions of the silicon wafer. The strain and rotation measurements are interpreted by finite element simulations. While confirming the basic findings of previously published studies, the present approach enables a potential reduction in the necessary pattern data size by about two orders of magnitude. We estimate that pattern resolutions in the order of 256×256 pixels should be enough to solve a majority of EBSD analysis tasks using pattern matching techniques.

Silicon, being the fundamental material for modern semiconductor devices, has seen continuous advancements to enhance its electrical and mechanical properties. Strain engineering is a well-established technique for improving the performance of silicon-based devices. In this paper, we propose a simple method for inducing and permanently maintaining strain in silicon through pure physical bending. By subjecting the silicon substrate to a controlled bending process, we demonstrate the generation of strain levels that persist even after the removal of external stress, with a maximum strain value of 0.4%. We present a comprehensive study of the mechanics behind this phenomenon, a full finite element mechanical model, and experimental verification of the bending-induced strain in Si membranes using electron backscatter diffraction measurements. Our findings show the potential of this approach for strain engineering in high-performance silicon-based technologies without resorting to complex and expensive fabrication techniques.

Pattern matching approaches to electron backscatter diffraction (EBSD) in the scanning electron microscope (SEM) provide qualitatively new possibilities for the microstructural analysis of chiral non-centrosymmetric phases due to the influence of dynamical electron diffraction effects on the formation of EBSD Kikuchi patterns. In the present study, we analyze the microstructure of polycrystalline alpha-quartz in an agate mineral sample. We identify characteristic intra-grain inversion domains of different handedness which are well-known from classical polarized light microscopy. As a result, the handedness-resolved microstructure of quartz can be imaged with the spatial and orientation resolution provided by EBSD in the SEM.

Using x-ray photoelectron diffraction (XPD) and angle-resolved photoemission spectroscopy, we study photoemission intensity changes related to changes in the geometric and electronic structure in the kagome metal CsV_3Sb_5 upon transition to an unconventional charge density wave (CDW) state. The XPD patterns reveal the presence of a chiral atomic structure in the CDW phase. Furthermore, using circularly polarized x-rays, we have found a pronounced non-trivial circular dichroism in the angular distribution of the valence band photoemission in the CDW phase, indicating a chirality of the electronic structure. This observation is consistent with the proposed orbital loop current order. In view of a negligible spontaneous Kerr signal in recent magneto-optical studies, the results suggest an antiferromagnetic coupling of the orbital magnetic moments along the c-axis. While the inherent structural chirality may also induce circular dichroism, the observed asymmetry values seem to be too large in the case of the weak structural distortions caused by the CDW.

Photoelectron diffraction (PED) is a powerful technique for resolving surface structures with sub-angstrom precision. At high photon energies, angle-resolved photoemission spectroscopy (ARPES) reveals PED effects, often challenged by small cross-sections, momentum transfer, and phonon scattering. X-ray PED (XPD) is not only an advantageous approach but also exhibits unexpected effects. We present a PED implementation for the spin-polarized relativistic Korringa-Kohn-Rostoker (SPRKKR) package to disentangle them, employing multiple scattering theory and a one-step photoemission model. Unlike conventional real-space approaches, our method uses a k-space formulation via the layer-KKR method, offering efficient and accurate calculations across a wide energy range (20-8000 eV) without angular momentum or cluster size convergence issues. Additionally, the alloy analogy model enables simulations of finite-temperature XPD and effects in soft/hard X-ray ARPES. Applications include modeling circular dichroism in angular distributions (CDAD) in core-level photoemission of Si(100) 2p and Ge(100) 3p, excited by 6000 eV photons with circular polarization.

Owing to its unique properties, N-polar GaN offers several advantages over Ga-polar GaN, particularly for applications in high power electronics. However, the growth of high-quality N-polar material is challenging. One dominant issue is the increased surface roughness, due to the occurrence of hexagonal-shaped hillocks, referred to as hexagons, on the material’s surface. Although there are different methods to reduce the density of these hillocks, such as the use of vicinal substrates or optimum growth conditions, the properties of such hillocks are not extensively studied. Here, we investigate the crystallographic and luminescence properties of these hexagonal features using the techniques of electron backscatter diffraction (EBSD) and cathodoluminescence (CL) hyperspectral imaging in the scanning electron microscope combined with micro-Raman mapping. CL revealed increased light emission from the top of the hexagons compared with the surrounding material. Additionally, dark spots in intensity images, associated with non-radiative recombination at threading dislocations, could be resolved on top of the hexagons, but not in the surrounding area, implying improved material quality of the hexagons. Extensive strain analysis using EBSD revealed that the hexagons are composed of equivalent triangular segments with tensile strain along symmetrically equivalent ⟨112¯0⟩ directions. As the hexagons become larger, this strain increases with the distance from the center. This was confirmed by mapping the Raman E2 (high) mode. Overall, this provides crucial insight into the strain state of these hexagonal features.

The remarkable physical properties of dental enamel can be largely attributed to the structure of the hydroxyapatite (HAp) crystallites on the sub-micrometre scale. Characterising the HAp microstructure is challenging, due to the nanoscale of individual crystallites and practical challenges associated with HAp examination using electron microscopy techniques. Conventional methods for enamel characterisation include imaging using transmission electron microscopy (TEM) or specialised beamline techniques, such as polarisation-dependent imaging contrast (PIC). These provide useful information at the necessary spatial resolution but are not able to measure the full crystallographic orientation of the HAp crystallites. Here we demonstrate the effectiveness of enamel analyses using transmission Kikuchi diffraction (TKD) in the scanning electron microscope, coupled with newly-developed pattern matching methods. The pattern matching approach, using dynamic template matching coupled with subsequent orientation refinement, enables robust indexing of even poor-quality TKD patterns, resulting in significantly improved data quality compared to conventional diffraction pattern indexing methods. The potential of this method for the analysis of nanocrystalline enamel structures is demonstrated by the characterisation of a human enamel TEM sample and the subsequent comparison of the results to high resolution TEM imaging. The TKD - pattern matching approach measures the full HAp crystallographic orientation enabling a quantitative measurement of not just the c-axis orientations, but also the extent of any rotation of the crystal lattice about the c-axis, between and within grains. Results presented here show how this additional information highlights potentially significant aspects of the HAp crystallite structure, including intra-crystallite distortion and the presence of multiple high angle boundaries between adjacent crystallites with rotations about the c-axis. These and other observations enable a more rigorous understanding of the relationship between HAp structures and the physical properties of dental enamel.

Electron backscatter diffraction (EBSD) patterns can exhibit Kikuchi bands with inverted contrast due to anomalous absorption. This can be observed, for example, on samples with nanoscale topography, in case of a low tilt backscattering geometry, or for transmission Kikuchi diffraction (TKD) on thicker samples. Three examples are discussed where contrast-inverted physics-based simulated master patterns have been applied to find the correct crystal orientation. As first EBSD example, self-assembled gold nanostructures made of Au fcc and Au hcp phases on single-crystal germanium were investigated. Gold covered about 12% of the mapped area, with only two thirds being successfully interpreted using standard Hough-based indexing. The remaining third was solved by brute force indexing using a contrast-inverted master pattern. The second EBSD example deals with maps collected at a non-tilted surface instead of the commonly used 70° tilted one. As TKD example, a jet-polished foil made of duplex stainless steel 2205 was examined. The thin part close to the hole edge producing normal-contrast patterns were standard indexed. The areas of the foil that become thicker with increasing distance from the edge of the hole produce contrast-inverted patterns. They covered three times the evaluable area and were successfully processed using the contrast-inverted master pattern. In the last example, inverted patterns collected at a non-tiled sample were mathematically inverted to normal contrast, and Hough/Radon-based indexing was successfully applied.

Photoelectron diffraction (PED) of core-level photoemission is an influential spectroscopic technique that provides valuable insights into the electronic and geometrical structure of materials at the atomic scale. In fact, it is not only a powerful method but also an unexpected effect. The choice of an appropriate theoretical formalism to interpret the experiments is therefore a necessity. Building on our previous successful work on the implementation of PED under the SPRKKR package, this study presents new and detailed experimental-theoretical comparisons of other core levels, providing deeper insights into material properties. We have calculated the circular dichroism in angular distributions (CDAD) for 3p, 3d and 4p of W(110) for application-specific purposes. The discriminant diffractogram between split corelevels is discussed. Above 50% difference in the spin-orbit doublets of 3d and 4p is reported. Hard X-rays (6000 eV) with right and left circularly polarized radiation (RCP and LCP, respectively) are used to generate photoelectrons. Through a comprehensive comparison of measured and calculated results, this study advances our understanding of PED simulations and their implications for materials characterization and discovery.

Recent years show a significant interest in the study of martensite tetragonality in steels [1].The tetragonality of martensite in general depends on the carbon content of the austenite before quenching.Almost 100 years of research have shown a linear dependence of tetragonality (the ratio c to a, c/a) on the carbon content of the steel.c/a = 1+0.045Xwhere X is the carbon content mass percentage.Studies of tetragonality were so far mainly carried out using X-ray diffraction.In X-ray diffraction studies, the signal comes from a large area of the sample, typically more than 1 mm 2 averaging the obtained result.The most promising technique for the local measurement of tetragonality appears to be Backscattered Electron Diffraction (EBSD), which allows surface measurements with steps of tens of nanometers or more.In recent years, new algorithms have been developed to analyze local changes in lattice parameter ratios based on EBSD patterns [2,3].Newly obtained results show that martensite tetragonality can be decreased by exposure to Ga + ions from focused ion beam (FIB).Small doses of 50 pC/μm 2 lead to decrease of the local tetragonality of the martensite at all investigated acceleration voltages (2-30 kV).Moreover, the retained austenite treated with gallium ions transformed into ferrite/or martensite which was not tetragonal.These results suggest that special attention should be paid for transmission electron microscopy (TEM) lamellae and atom probe tomography (APT) sample preparation of tetragonal martensite.Another factor leading to change of the measured tetragonality is deformation which can happen during sample preparation or on purpose and it is causing decrease of the martensite tetragonality.Examples of both ion beam and deformation induced tetragonality loss will be discussed during the presentation [4].