Spin fluctuations and possible superconductivity from canting in Sr₂IrO₄

The perovskite iridates share much of the phenomenology of high T_c superconducting cuprates. Close to the fermi surface, the bands structure of the iridate Sr₂IrO₄ is mainly of a pseudospin J=1/2 character. In analogy to the cuprates, models for these bands predict a possible d-wave superconductivity. However, it is possible that inter-band hybridization may be important for determining the type and magnitude of possible pairing functions.  Therefore, multiorbital models are key to understanding how possible superconducting regimes could become more accessible.

Studies have shown a strong coupling between magnetic order and structural changes in Sr₂IrO₄. Effects such as strain modify bond lengths and the staggered rotations of the lattice, which in turn affects the canted antiferromagnetic order. In this work, we study possible spin fluctuation mediated superconductivity in a model of Sr₂IrO₄ were canted rotations are included. These inherently multiorbital properties are considered in both the electron and hole doped regimes. The effects of symmetry breaking spin fluctuations and manipulating the band structure via strain are thus studied in several possible superconducting regimes. We comment on ways to increase the chance of superconductivity.