Published August 26, 2025 | Published
Journal Article Open

Ab initio Maxwell-Bloch approach for x-ray excitations in two-dimensional materials

  • 1. ROR icon Technical University of Berlin
  • 2. ROR icon California Institute of Technology

Abstract

The combination of Maxwell and Bloch equations is an ideal framework to describe ultrafast time-resolved x-ray experiments on an attosecond timescale in crystals. However, broadband experiments such as x-ray absorption near-edge spectroscopy or resonant inelastic x-ray scattering require detailed knowledge of the electronic structure and transition matrix elements. Here, we show how to fill this gap by combining the Maxwell-Bloch formalism with first-principles calculations treating explicitly the core states. The resulting x-ray absorption spectrum recovers key spectral signatures which were missing in previous work relying on a semiempirical tight-binding approach.

Copyright and License

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Acknowledgement

We thank Dhruv Desai (Caltech) and Yao Luo (Caltech) for fruitful discussions. We acknowledge financial support from the Deutsche Forschungsgemeinschaft (DFG) through KN427 14-1, Theory of core-exciton dynamics and nonlinear x-ray spectroscopy (Project No. 527838492) (D.C., J.S., A.K.). I.M. and M.B. acknowledge support by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award No. DE-SC0021266.

Data Availability

The data that support the findings of this article are not publicly available. The data are available from the authors upon reasonable request.

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Created:
September 4, 2025
Modified:
September 4, 2025