Superconducting phase diagram in a model for tetragonal and cubic systems with strong antiferromagnetic correlations

Abstract

We calculate the superconducting phase diagram as a function of temperature and z-axis anisotropy in a model for tetragonal and cubic systems having strong antiferromagnetic fluctuations. The formal basis for our calculations is the fluctuation exchange approximation applied to the single-band Hubbard model near half-filling. For nearly cubic lattices, two superconducting phase transitions are observed as a function of temperature with the low-temperature state having the time-reversal symmetry-breaking form dx2−y2±id3z2−r2. With increasing tetragonal distortion, the time-reversal symmetry-breaking phase is suppressed, giving way to only dx2−y2 or d3z2−r2 single-component phases. Based on these results, we propose that a time-reversal symmetry-breaking superconducting state may be found in cubic systems with pairing driven by antiferromagnetic fluctuations.

Source-reported materials — not catalogue approval

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