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The Center for Bright Beams, A National Science Foundation Science and Technology Center

Special Seminar: Ab initio Quantum-Mechanical Analysis of Semiconducting Photocathode Materials with Caterina Cocchi

Thu, 01/20/2022, 11:00am - 12:00pm

Caterina Cocchi, Carl von Ossietzky Universität Oldenburg, Institut für Physik, Oldenburg, Germany

Humboldt-Universität zu Berlin, Institut für Physik & IRIS Adlershof, Berlin, Germany

The search for next-generation photocathode materials requires in-depth knowledge of their microscopic properties, including energetic and thermodynamic stability, electronic structure, and (quasi-)particle interactions. Quantum mechanical ab initio methods, such as density-functional theory and many-body perturbation theory, are the most suitable tools to address these issues, as they enable parameter-free investigations of materials without the need for any a priori synthesis or experimental characterization. The combination of such state-of-the-art approaches with the most recent computational techniques for high-throughput screening are expected to be a game changer in this research area.

  In this talk, I will present the work of my group in this field mainly concerning alkali antimonide and telluride materials. After introducing the adopted theoretical/computational approach, I will discuss our findings which confirm that both Cs- and Na-based antimonides offer favorable electronic and optical characteristics as photocathode materials. I will demonstrate the ability of the adopted methodology to provide insight into X-ray spectral fingerprints as a tool to assess the stoichiometry and compositions of the samples, considering cesium antimonides as exemplary systems. Finally, I will conclude my presentation with our first results on high-throughput screening of binary cesium antimonide and telluride compounds.