Superconducting Order Parameter and Bosonic Mode in Hydrogen-Substituted NdFeAsO${}_{0.6}$H${}_{0.36}$ Revealed by Multiple Andreev Reflection Spectroscopy

Abstract

Using intrinsic multiple Andreev reflections effect (IMARE) spectroscopy, we studied ballistic superconductor - normal metal - superconductor (SnS) contacts in layered oxypnictide superconductors NdFeAsO${}_{0.6}$H${}_{0.36}$ with critical temperatures $T_c=45-48$ K. We directly determined the magnitude of two bulk superconducting order parameters, the large gap ${\Delta }_L\approx 10.4$ meV, and a possible small gap ${\Delta }_S\approx 1.8$ meV, and their temperature dependence. Additionally, a resonant coupling with a characteristic bosonic mode was observed. The boson energy at 4.2 K, ${\epsilon }_0=10.5-11.0$ meV being less than the indirect gap (${\Delta }_L<{\epsilon }_0<{\Delta }_L+{\Delta }_S$).

10 pages, 6 figures

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Cited by in corpus (1)

• Superconductivity of underdoped PrFeAs(O,F) investigated via point-contact spectroscopy and nuclear magnetic resonance