Fractionalized fermionic multicriticality in anisotropic Kitaev spin-orbital liquids

Fuente: arXiv
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Autori principali: Fornoville, Max, Janssen, Lukas
Natura: Preprint
Pubblicazione: 2025
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author Fornoville, Max
Janssen, Lukas
author_facet Fornoville, Max
Janssen, Lukas
contents We study the low-temperature phase diagram of quantum Kitaev-Heisenberg spin-orbital models with XXZ anisotropy on the honeycomb lattice. Within a parton mean-field theory, we identify three different quantum phases, distinguished by their symmetries. Besides a disordered spin-orbital liquid with unbroken U(1) x Z2 spin rotational symmetry, there are two orbital liquid phases characterized by spin long-range order. In these phases, the spin rotational symmetry is spontaneously broken down to residual U(1) and Z2 symmetries, respectively. The symmetric spin-orbital liquid features three flavors of linearly dispersing gapless Majorana fermions. In the symmetry-broken phases, one of the three Majorana excitations remains gapless, while the other two acquire a band gap. The transitions from the symmetric to the symmetry-broken phases are continuous and fall into the fractionalized Gross-Neveu-Z2* and Gross-Neveu-SO(2)* universality classes, respectively. The transition between the ordered phases is discontinuous. Using a renormalization group analysis based on the epsilon expansion, we demonstrate that the triple point in the phase diagram features fractionalized fermionic multicriticality with emergent SO(3) symmetry.
format Preprint
id arxiv_https___arxiv_org_abs_2505_01493
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fractionalized fermionic multicriticality in anisotropic Kitaev spin-orbital liquids
Fornoville, Max
Janssen, Lukas
Strongly Correlated Electrons
High Energy Physics - Theory
We study the low-temperature phase diagram of quantum Kitaev-Heisenberg spin-orbital models with XXZ anisotropy on the honeycomb lattice. Within a parton mean-field theory, we identify three different quantum phases, distinguished by their symmetries. Besides a disordered spin-orbital liquid with unbroken U(1) x Z2 spin rotational symmetry, there are two orbital liquid phases characterized by spin long-range order. In these phases, the spin rotational symmetry is spontaneously broken down to residual U(1) and Z2 symmetries, respectively. The symmetric spin-orbital liquid features three flavors of linearly dispersing gapless Majorana fermions. In the symmetry-broken phases, one of the three Majorana excitations remains gapless, while the other two acquire a band gap. The transitions from the symmetric to the symmetry-broken phases are continuous and fall into the fractionalized Gross-Neveu-Z2* and Gross-Neveu-SO(2)* universality classes, respectively. The transition between the ordered phases is discontinuous. Using a renormalization group analysis based on the epsilon expansion, we demonstrate that the triple point in the phase diagram features fractionalized fermionic multicriticality with emergent SO(3) symmetry.
title Fractionalized fermionic multicriticality in anisotropic Kitaev spin-orbital liquids
topic Strongly Correlated Electrons
High Energy Physics - Theory
url https://arxiv.org/abs/2505.01493