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arXiv · 1511.03289

Triplet FFLO Superconductivity in the doped Kitaev-Heisenberg Honeycomb Model

Tianhan Liu·Cécile Repellin·Benoît Douçot·Nicolas Regnault·Karyn Le Hur
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Abstract

We provide analytical and numerical evidence of a spin-triplet FFLO superconductivity in the itinerant Kitaev-Heisenberg model (anti-ferromagnetic Kitaev coupling and ferromagnetic Heisenberg coupling) on the honeycomb lattice around quarter filling. The strong spin-orbit coupling in our model leads to the emergence of 6 inversion symmetry centers for the Fermi surface at non zero momenta in the first Brillouin zone. We show how the Cooper pairs condense into these non-trivial momenta, causing the spatial modulation of the superconducting order parameter. Applying a Ginzburg-Landau expansion analysis, we find that the superconductivity has three separated degenerate ground states with three different spin-triplet pairings. This picture is also supported by exact diagonalizations on finite clusters.

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Tianhan Liu, Cécile Repellin, Benoît Douçot, Nicolas Regnault, Karyn Le Hur. 2015-11-10. Triplet FFLO Superconductivity in the doped Kitaev-Heisenberg Honeycomb Model. https://doi.org/10.1103/physrevb.94.180506

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