Anyon polarons as a window into competing phases of the Kitaev honeycomb model under a Zeeman field
Phys. Rev. B 111, 245140 – Published 20 June, 2025
DOI: https://doi.org/10.1103/xxym-pc1t
Abstract
We compute the spectra of anyon quasiparticles in all three superselection sectors of the Kitaev model (i.e., visons, fermions, and bosons), perturbed by a Zeeman field away from its exactly solvable limit, to gain insights on the competition of its non-Abelian spin-liquid with other nearby phases, such as the mysterious intermediate state observed in the antiferromagnetic model. In both ferro- and antiferromagnetic models, we find that the fermions and visons become gapless at nearly identical critical Zeeman couplings. In the ferromagnetic model, this is consistent with a direct transition into a polarized state. In the antiferromagnetic model, this implies that previous theories of the intermediate phase viewed as a spin liquid with a different fermion Chern number are inadequate, as they presume that the vison gap does not close. In the antiferromagnetic model, we also find that a bosonic quasiparticle becomes gapless at nearly the same critical field as the fermions and visons. This boson carries the quantum numbers of an antiferromagnetic order parameter, suggesting that the intermediate phase may possess spontaneously broken symmetry with this order.
