Low-energy electron microscopy intensity-voltage data – factorization, sparse sampling, and classification

Masia, Francesco ORCID: https://orcid.org/0000-0003-4958-410X, Langbein, Wolfgang ORCID: https://orcid.org/0000-0001-9786-1023, Fischer, Simon, Krisponeit, Jon-Olaf and Falta, Jens 2023. Low-energy electron microscopy intensity-voltage data – factorization, sparse sampling, and classification. Journal of Microscopy 289 (2) , pp. 91-106. 10.1111/jmi.13155

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Abstract

Low-energy electron microscopy (LEEM) taken as intensity-voltage (I-V) curves provides hyperspectral images of surfaces, which can be used to identify the surface type, but are difficult to analyze. Here, we demonstrate the use of an algorithm for factorizing the data into spectra and concentrations of characteristic components () for identifying distinct physical surface phases. Importantly, is an unsupervised and fast algorithm. As example data we use experiments on the growth of praseodymium oxide or ruthenium oxide on ruthenium single crystal substrates, both featuring a complex distribution of coexisting surface components, varying in both chemical composition and crystallographic structure. With the factorization result a sparse sampling method is demonstrated, reducing the measurement time by 1-2 orders of magnitude, relevant for dynamic surface studies. The concentrations are providing the features for a support vector machine (SVM) based supervised classification of the surface types. Here, specific surface regions which have been identified structurally, via their diffraction pattern, as well as chemically by complementary spectro-microscopic techniques, are used as training sets. A reliable classification is demonstrated on both exemplary LEEM I-V datasets.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy Biosciences
Publisher:	Wiley
ISSN:	1365-2818
Date of First Compliant Deposit:	24 October 2022
Date of Acceptance:	17 October 2022
Last Modified:	02 May 2023 12:14
URI:	https://orca.cardiff.ac.uk/id/eprint/153727

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