Superconductivity has been found in RuN films obtained by reactive magnetron sputtering. This is a novel member of the metal nitride superconductors family. The critical temperature of the superconducting transition varies depending on the substrate and ranges from 0.77 K to 1.29 K. The parameters of the crystal lattice of superconducting films have been determined: the lattice is distorted cubic with parameters a=b=c=4.5586 \AA , α=β=γ=87.96∘. A zero temperature upper critical magnetic field Hc2(0) and the coherence length were found from the experimental data using WHH model. Hc2(0)=2.3 T- 4.1 T for different substrates and exceeds the upper paramagnetic limit, as well as ξ=12 nm. An s-wave single band energy gap Δ(0)=0.19 meV was revealed by self-field critical current experiment at temperatures down to 10 mK, 2Δ/kTc=5.5 exceeding the BCS ratio 3.5.
@article{arxiv.2310.09526,
title = {Superconductivity in thin films of RuN},
author = {A. S. Ilin and A. O. Strugova and I. A. Cohn and V. V. Pavlovskiy and A. V. Sadakov and O. A. Sobolevskiy and L. A. Morgun and V. P. Matrovitskii and G. V. Rybalchenko and S. V. Zaitsev-Zotov},
journal= {arXiv preprint arXiv:2310.09526},
year = {2024}
}