Superconducting Energy Scales and Anomalous Dissipative Conductivity in Thin Films of Molybdenum Nitride
| Autor: | Lena Daschke, Jeffrey A. Klug, Marc Scheffler, Uwe S. Pracht, Martin Dressel, Julian Simmendinger, Thomas Proslier |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Superconductivity
Physics Condensed matter physics Transition temperature Condensed Matter - Superconductivity FOS: Physical sciences 02 engineering and technology Nitride 021001 nanoscience & nanotechnology 01 natural sciences Superfluidity Superconductivity (cond-mat.supr-con) Excited state Condensed Matter::Superconductivity 0103 physical sciences Quasiparticle Charge carrier 010306 general physics 0210 nano-technology Energy (signal processing) |
| Popis: | We report investigations of molybdenum nitride (MoN) thin films with different thickness and disorder and with superconducting transition temperature 9.89 K $\ge{T_c}\ge$ 2.78 K. Using terahertz frequency-domain spectroscopy we explore the normal and superconducting charge carrier dynamics for frequencies covering the range from 3 to 38 cm$^{-1}$ (0.1 to 1.1 THz). The superconducting energy scales, i.e. the critical temperature $T_c$, the pairing energy $\Delta$, and the superfluid stiffness $J$, and the superfluid density $n_s$ can be well described within the Bardeen-Cooper-Schrieffer theory for conventional superconductors. At the same time, we find an anomalously large dissipative conductivity, which cannot be explained by thermally excited quasiparticles, but rather by a temperature-dependent normal-conducting fraction, persisting deep into the superconducting state. Our results on this disordered system constrain the regime, where discernible effects stemming from the disorder-induced superconductor-insulator transition possibly become relevant, to MoN films with a transition temperature lower than at least 2.78 K. Comment: 9 Pages |
| Databáze: | OpenAIRE |
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