Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 71: Poster: Plasmonics and Nanooptics

O 71.7: Poster

Wednesday, March 20, 2024, 18:00–20:00, Poster D

Non-equilibrium electrons generated from the extended two-temperature model to drive chemical dynamics at surfaces — •Henry T. Snowden and Reinhard J. Maurer — University of Warwick, Coventry, UK

A mechanistic understanding of ultrafast light-matter interactions with surfaces and nanoparticles is invaluable for the study of ultrafast dynamics at surfaces. The two-temperature model (2TM) represents the most common approach to model light-matter interaction. It assumes that electrons remain in a Fermi-Dirac distribution, which is heated by a laser source term. This assumption is invalid immediately after a laser pulse, where a short-lived population of non-equilibrium electrons is generated. Here we will explore the extended two-temperature model (e2TM), proposed by Carpene [Phys Rev B 74, 24301 (2006)], including further extensions from Uehlein et al. [Nanomaterials 12, 1655 (2022)]. We will show that the e2TM captures information consistent with simulations based on the Boltzmann transport equation while maintaining much of the simplicity and computational efficiency of the 2TM. We incorporate many parameters directly calculated from first principles, such as the density-of-states (DOS) and properties derived thereof. We present a systematic assessment of the dependence of the e2TM on the type of metal and surface termination and directly relate our results to time-resolved spectroscopy results. Finally, we will examine the necessary properties of a material required to generate long-lived non-equilibrium electrons and suggest possible material candidates.

Keywords: Light-Matter Interactions; Surface Chemistry; Non-equilibrium dynamics