Versatile control of the superconducting transition temperature in anti-ThCrSi-type YOBi H, Li, or F doping.

In YOBi with Bi square net, H substitution and Li intercalation led to higher superconducting transition temperature (), while F substitution led to lower , where is universally scaled by unit cell tetragonality /. Li intercalated YOBi showed a higher than previously reported YOBi even for the similar /.

Tetragonality induced superconductivity in anti-ThCrSi-type REOBi (RE = rare earth) with Bi square nets.

We report a series of layered superconductors, anti-ThCrSi-type REOBi (RE = rare earth), composed of electrically conductive Bi square nets and magnetic insulating REO layers. Superconductivity was induced by separating the Bi square nets as a result of excess oxygen incorporation, irrespective of the presence of magnetic ordering in REO layers. Intriguingly, the transition temperature of all REOBi including nonmagnetic YOBi was approximately scaled by unit cell tetragonality (c/a), implying a key role in the relative separation of the Bi square nets to induce superconductivity.

Superconductivity in Anti-ThCrSi-type ErOBi Induced by Incorporation of Excess Oxygen with CaO Oxidant.

Recently, superconductivity was induced by expanding interlayer distance between Bi square nets in anti-ThCrSi-type YOBi through incorporation of excess oxygen with increased nominal amount of oxygen. However, such oxygen incorporation was applicable to only YOBi among ROBi ( R = rare earth metal), probably due to a larger amount of oxygen incorporation for YOBi. In this study, the interlayer distance in ErOBi was increased by cosintering with CaO, which served as an oxidant, indicating that excess oxygen was incorporated in ErOBi.