Berlin 2024 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 20: Data Driven Material Science: Big Data and Workflows III
MM 20.1: Vortrag
Dienstag, 19. März 2024, 10:15–10:30, C 243
Bulk and Surface Properties of cesium-telluride Photocathode Materials via High-Throughput Density Functional Theory Calculations — •Holger-Dietrich Saßnick1 and Caterina Cocchi1,2 — 1Carl von Ossietzky Universität Oldenburg, Physics Department, 26129 Oldenburg, Germany — 2Humboldt-Universität zu Berlin, Physics Department and IRIS Adlershof, 12489 Berlin, Germany
Cesium-based photocathodes such as cesium-telluride are commonly used as electron sources in particle accelerators but the lack of knowledge of their crystal structure and stoichiometry during synthesis hinders their control. To predict which compounds are more likely to form and to characterize their properties, we apply a high-throughput workflow based on density functional theory calculations. Firstly, we calculate the formation energies and electronic properties of bulk phases obtained from computational databases employing the meta-GGA functional SCAN, which is known to provide accurate results for these systems [Saßnick & Cocchi, Electron. Struct. 3, 027001 (2021)]. Our results indicate that a large number of different crystal structures may form and coexist in actual samples [Saßnick & Cocchi, J. Chem. Phys. 156, 104108 (2022)]. In a second step, surface properties, which play a fundamental role in the photocathode performance, are calculated for a selected set of stable bulk crystals. The studied surfaces exhibit diverse properties ranging from semiconducting to metallic character with the latter being formed by facets terminated with an excess of metallic species.
Keywords: Photocathodes; Cesium-telluride; Surfaces; Density functional theory; High-throughput