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DS: Fachverband Dünne Schichten

DS 8: Optical Analysis of Thin Films I

DS 8.2: Vortrag

Mittwoch, 19. März 2025, 12:15–12:30, H3

Ultrafast Charge Carrier Dynamics in Niobium Probed in the Visible Spectral Range — •Noah Stiehm¹, Shirly Espinoza², Mateusz Rebarz², Saul Vazquez Miranda², Erik Müller³, Hannes Töpfer³, Stefan Krischok¹, and Rüdiger Schmidt-Grund¹ — ¹Technische Universität Ilmenau, Fachgebiet Technische Physik I, Weimarer Straße 32, 98693 Ilmenau, Germany — ²ELI Beamlines Facility, The Extreme Light Infrastructure ERIC, Za Radnicí 835, 25241 Dolní Břežany, Czech-Republic — ³Technische Universität Ilmenau, Fachgebiet Theoretische Elektrotechnik, Helmholtzplatz 2, 98693 Ilmenau, Germany

With the recently developed experimental method of femtosecond time-resolved spectroscopic ellipsometry (trSE) [1], it is possible to obtain the transient dielectric function of a sample after excitation in a pump-probe scheme. We present results of applying the technique to study the ultrafast charge carrier dynamics in the transition metal Niobium. We show that it is possible to observe bleaching in the dielectric function for several 100 picoseconds and up to 1 nanosecond, depending on the pump wavelength, resulting from exciting charge carriers into higher conduction bands, where they relax into band minima and remain stable for some time until recombination.

The initial results from this study at room temperature provide valuable insight into the ultrafast charge carrier dynamics and good motivation to conduct further investigations under cryogenic conditions in the superconducting phase.

[1] S. Richter et al., Rev. Sci. Instrum. 92, 033104 (2021).

Keywords: ultra-fast; charge carrier dynamics; time-resolved ellipsometry; femtosecond; pump-probe