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Transforming 4D-STEM Data: From Diffraction to Cepstra & Aberrations to Brightness

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dc.contributor.authorCueva, Paul
dc.contributor.chairMuller, David Anthony
dc.contributor.committeeMemberHoffstaetter, Georg Heinz
dc.contributor.committeeMemberSelman, Bart
dc.date.accessioned2021-09-09T17:40:41Z
dc.date.available2021-09-09T17:40:41Z
dc.date.issued2021-05
dc.description53 pages
dc.description.abstractThe goal of microscopy is to take position-resolved data of things invisible & small and transform that data into something meaningful & macroscopic. In the case of scanning transmission electron microscopy (STEM) we generate position resolved data by raster scanning a focused beam of highly accelerated electrons—also called the probe or the incident beam—on a thin sample and measuring the properties of the electrons that pass through the sample. If we know certain properties of the incident electrons, say their momentum, and then measure that property after having interacted with the sample, we can infer properties about the sample, such as the scattering potential & therefore the locations of the atoms within the sample. We then generate an image where the pixel values represent the measured properties. Obtaining an image that represents the properties of a material lets us understand & convey what is happening in ways that few other forms of science communication can. In this Dissertation, I discuss the concepts behind momentum-resolved STEM (4D-STEM); first with a general presentation of the limiting factors, followed by a more in-depth look at how we refine our measurements and the process by which we transform them into meaningful representations. I show that brightness preservation serves as a better optimization metric than aberration minimization. Finally, I discuss a new physically motivated data transformation that simplifies analysis of 4D-STEM data for high-precision strain measurement & robust grain identification.
dc.identifier.doihttps://doi.org/10.7298/fy75-sf69
dc.identifier.otherCueva_cornellgrad_0058F_12434
dc.identifier.otherhttp://dissertations.umi.com/cornellgrad:12434
dc.identifier.urihttps://hdl.handle.net/1813/109727
dc.language.isoen
dc.rightsAttribution-NonCommercial-ShareAlike 4.0 International
dc.rights.urihttps://creativecommons.org/licenses/by-nc-sa/4.0/
dc.subjectAberrations
dc.subjectDiffraction
dc.subjectElectron Microscopy
dc.subjectImage Processing
dc.subjectSTEM
dc.subjectTEM
dc.titleTransforming 4D-STEM Data: From Diffraction to Cepstra & Aberrations to Brightness
dc.typedissertation or thesis
dcterms.licensehttps://hdl.handle.net/1813/59810
thesis.degree.disciplineApplied Physics
thesis.degree.grantorCornell University
thesis.degree.levelDoctor of Philosophy
thesis.degree.namePh. D., Applied Physics

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