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  • Letter
  • Open Access

Femtosecond dynamics of electrons in noble metals: Orientational relaxation in momentum space and the Drude relaxation rate

Jonas Grumm* and Andreas Knorr†

  • *Contact author: j.grumm@tu-berlin.de
  • †Contact author: andreas.knorr@tu-berlin.de
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Phys. Rev. B 112, L241402 – Published 1 December, 2025

DOI: https://doi.org/10.1103/nq66-bzwj

Abstract

We investigate the momentum-resolved dynamics of conduction electrons in noble metals following ultrashort optical excitation with linearly polarized light. Using a momentum-resolved Boltzmann equation approach for electron-phonon interaction, we solve for the combined effects of orientational relaxation, thermalization, and cooling. We introduce momentum orientational relaxation as the initial step in the equilibration of an optically excited nonequilibrium electron gas by highlighting its importance for the optical response of noble metals as the dephasing of the Drude model. The numerical results for gold reveal that orientational relaxation exists already for linear optical excitations and dominates on time scales on the first tens of femtoseconds after excitation. Also incorporating thermalization and cooling on times up to a few picoseconds, our approach provides a simultaneous description of optical and thermal properties of noble metals under optically induced nonequilibrium conditions.

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See Also

Theory of nonlinear electron relaxation in thin gold films and their signatures in optical observables

Jonas Grumm, Malte Selig, Holger Lange, and Andreas Knorr
Phys. Rev. B 112, 245402 (2025)

Article Text

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Phys. Rev. B 112, L241402– Published 1 December, 2025
  • Received 29 April 2025
  • Revised 1 October 2025
  • Accepted 3 November 2025
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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.

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