Global phase diagram, possible chiral spin liquid and topological superconductivity in the triangular Kitaev-Heisenberg model

Abstract

The possible ground states of the undoped and doped Kitaev-Heisenberg model on a triangular lattice are studied. For the undoped system, a combination of the numerical exact diagonalization calculation and the four-sublattice transformation analysis suggests one possible exotic phase and four magnetically ordered phases including a collinear stripe pattern and a noncollinear spiral pattern in the global phase diagram. The exotic phase near the antiferromagnetic (AF) Kitaev point is further investigated by using the Schwinger-fermion mean-field method, and we obtain an energetically favorable $Z_2$ chiral spin liquid with a Chern number $\pm 2$ as a promising candidate. At finite doping, we find that the AF Heisenberg coupling supports an $s$-wave or a $d_{x^2-y^2}+i{d}_{xy}$-wave superconductivity (SC), while the AF and the ferromagnetic Kitaev interactions favor a $d_{x^2-y^2}+i{d}_{xy}$-wave SC and a time-reversal invariant topological $p$-wave SC, respectively. Possible experimental realizations and related candidate materials are also discussed.

Published version: References updated, and the electron doped phase diagram was added

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Cited by in corpus (11)

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• Kitaev-like honeycomb magnets: Global phase behavior and emergent effective models
• Semiclassical ground-state phase diagram and multi-Q phase of a spin-orbit coupled model on triangular lattice
• Finite-temperature properties of the Kitaev-Heisenberg models on kagome and triangular lattices studied by improved finite-temperature Lanczos methods
• Revisiting the Kitaev material candidacy of Ir4+ double perovskite iridates
• Quantum spin liquid ground states of the Heisenberg-Kitaev model on the triangular lattice
• Quantum paramagnet in a $\pi$ flux triangular lattice Hubbard model
• Topological superconductivity in the extended Kitaev-Heisenberg model
• Spinon Majorana fermions