Classifying superconductivity in an infinite-layer nickelate Nd${}_{0.8}$Sr${}_{0.2}$NiO${}_2$

Recently Li et al (2019 Nature 572 624) discovered a new type of oxide superconductor Nd0.8Sr0.2NiO2 with T${}_c$ = 14 K. To classify superconductivity in this infinite-layer nickelate experimental upper critical field, B${}_{c2}$(T), and the self-field critical current densities, J${}_c$(sf,T), reported by Li et al (2019 Nature 572 624), are analysed in assumption of s-, d-, and p-wave pairing symmetries and single- and multiple-band superconductivity. Based on deduced the ground-state superconducting energy gap, $\mathrm{\Delta }$(0), the London penetration depth, $\lambda$(0), the relative jump in electronic specific heat at Tc, $\mathrm{\Delta }$C/C, and the ratio of 2$\mathrm{\Delta }$(0)/k${}_B$T${}_c$, we conclude that Nd0.8Sr0.2NiO2 is type-II high-$\kappa$ weak-coupled single-band s-wave superconductor.