Possible superconductivity in the electron-doped chromium pnictide LaOCrAs

Abstract

We constructed an effective tight-binding model with five Cr 3d orbitals for LaOCrAs according to first-principles calculations. Based on this model, we investigated possible superconductivity induced by interactions in doped LaOCrAs using the functional renormalization group (FRG). We find that there are two domes of superconductivity in electron-doped LaOCrAs. With increasing electron doping, the ground state of the system evolves from G-type antiferromagnetism in the parent compound to an incipient s±−wave superconducting phase dominated by electron bands derived from the d3z2−r2 orbital as the filling is above 4.2 electrons per site on the d orbitals of Cr. The gap function has strong octet anisotropy on the Fermi pocket around the zone center and diminishes on the other pockets. In electron over-doped LaOCrAs, the system develops a dx2−y2-wave superconducting phase and the active band derives from the dxy orbital. In between the two superconducting domes, a time-reversal symmetry breaking s+id SC phase is likely to occur. The typical transition temperature for SC is estimated to lie between that of iron pnictides and cuprates. We also find the s±−wave superconducting phase in the hole-doped case.

Source-reported materials — not catalogue approval

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