Classifying superconductivity in an infinite-layer nickelate Nd0.8Sr0.2NiO2

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, Delta(0), the London penetration depth, lambda(0), the relative jump in electronic specific heat at T-c , Delta C/C , and the ratio of 2 Delta(0)/k(B)T(c) , we conclude that Nd0.8Sr0.2NiO2 is type II high-x weak-coupled single-band s-wave superconductor.