Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 11: Superconductivity: Poster
TT 11.4: Poster
Montag, 17. März 2025, 15:00–18:00, P4
THz spectroscopy on superconducting ZrN thin films — •Ozan Saritas1, Frederik Bolle1, Martin Dressel1, Roman Potjan2, Marcus Wislicenus2, and Marc Scheffler1 — 11. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany — 2Fraunhofer Institute for Photonic Microsystems (IPMS), Center Nanoelectronic Technologies (CNT), Dresden, Germany
The recent large-scale preparation of superconducting ZrN thin films is of interest for potential quantum technology applications [1]. Therefore, here we use THz frequency domain spectroscopy to investigate the superconducting electrodynamics of ZrN thin films, with thickness between 20 nm and 50 nm, grown on 300 mm-standard silicon substrates. We have measured the transmission and phase shift of THz radiation passing through the ZrN films, and we have obtained the frequency-dependent dielectric function. We thus acquired characteristic material quantities such as the temperature-dependent superconducting energy gap 2Δ(T) and superfluid density ns(T). With decreasing thickness, there is a clear trend towards a lower critical temperature Tc, a reduced 2Δ(T=0), and a lower ns(T=0). While the overall behavior is similar to BCS predictions, thinner films exhibit values for the ratio 2Δ(T=0)/(kB Tc) that deviate more from the canonical value.
Additionally, a novel analysis of the temperature-dependent shift of Fabry-Perot transmission resonance frequencies of superconducting thin-film samples was performed.
[1] R. Potjan et al, Appl. Phys. Lett. 123, 172602 (2023)
Keywords: ZrN; THz spectroscopy; superconducting thin films; superconductors for quantum technologies; electrodynamics of superconductors