Dynamic control of X-ray core-exciton resonances by Coulomb screening in photoexcited semiconductors

Dynamic control of X-ray core-exciton resonances by Coulomb screening in photoexcited semiconductors

Abstract Excitonics is an emerging field focused on exploiting and manipulating excitons generated through light-matter interactions. Advancing the field into X-ray excitonics requires precise energy and time control of core-exciton resonances, enabling non-linear X-ray phenomena such as element-spe...

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Main Authors: Thomas C. Rossi, Lu Qiao, Conner P. Dykstra, Ronaldo Rodrigues Pela, Richard Gnewkow, Rachel F. Wallick, John H. Burke, Erin Nicholas, Anne Marie March, Gilles Doumy, D. Bruce Buchholz, Christiane Deparis, Jesús Zúñiga-Pérez, Michael Weise, Klaus Ellmer, Mattis Fondell, Claudia Draxl, Renske M. van der Veen
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Communications Materials
Online Access:https://doi.org/10.1038/s43246-025-00909-w
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Summary:Abstract Excitonics is an emerging field focused on exploiting and manipulating excitons generated through light-matter interactions. Advancing the field into X-ray excitonics requires precise energy and time control of core-exciton resonances, enabling non-linear X-ray phenomena such as element-specific X-ray transient gratings, and advancing material characterization. To achieve these objectives, it is essential to comprehend the role of many-body effects governing core-exciton dynamics. In this work, we address this challenge by combining experiments with an ab initio approach specifically developed to interpret pump-probe excitations. Applied to the prototypical wide-bandgap semiconductor ZnO, first-principles calculations reproduce experimental results and unveil how the density and distribution of photoexcited carriers dynamically tune Coulomb screening, thereby controlling core-exciton binding energies, while Pauli blocking remains negligible. These insights inform a method for dynamically controlling core-exciton resonances at absorption edges, achieving either a uniform spectral blue shift caused by thermalized carrier distributions on picosecond timescales, or distinct blue shifts for individual resonances, driven by time-dependent carrier distributions on femtosecond timescales.
ISSN:2662-4443

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