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Phases and quantum phase transitions in an anisotropic ferromagnetic Kitaev-Heisenberg- Γ magnet
A. Nanda, , S. Bhattacharjee
Published in American Physical Society
Volume: 102
Issue: 23
We study the spin-1/2 ferromagnetic Heisenberg-Kitaev-Γ model in the anisotropic (Toric code) limit to reveal the nature of the quantum phase transition between the gapped Z2 quantum spin liquid and a spin-ordered phase (driven by Heisenberg interactions) as well as a trivial paramagnet (driven by pseudodipolar interactions Γ). The transitions are obtained by a simultaneous condensation of the Ising electric and magnetic charges - the fractionalized excitations of the Z2 quantum spin liquid. Both these transitions can be continuous and are examples of deconfined quantum critical points. Crucial to our calculations are the symmetry implementations on the soft electric and magnetic modes that become critical. In particular, we find strong constraints on the structure of the critical theory arising from time reversal and lattice translation symmetries with the latter acting as an anyon permutation symmetry that endows the critical theory with a manifestly self-dual structure. We find that the transition between the quantum spin liquid and the spin-ordered phase belongs to a self-dual modified Abelian Higgs field theory while that between the spin liquid and the trivial paramagnet belongs to a self-dual Z2 gauge theory. We also study the effect of an external Zeeman field to show an interesting similarity between the polarized paramagnet obtained due to the Zeeman field and the trivial paramagnet driven pseudodipolar interactions. Interestingly, both the spin liquid and the spin-ordered phases have easily identifiable counterparts in the isotropic limit and the present calculations may shed insights into the corresponding transitions in the material relevant isotropic limit. © 2020 American Physical Society.
About the journal
JournalData powered by TypesetPhysical Review B
PublisherData powered by TypesetAmerican Physical Society
Open AccessNo