Nature of the Topological Transition of the Kitaev Model in [111] Magnetic Field

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Hauptverfasser: Thiagarajan, S., Watson, C., Yzeiri, T., Hu, H., Uchoa, B., Krüger, F.
Format: Preprint
Veröffentlicht: 2025
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author Thiagarajan, S.
Watson, C.
Yzeiri, T.
Hu, H.
Uchoa, B.
Krüger, F.
author_facet Thiagarajan, S.
Watson, C.
Yzeiri, T.
Hu, H.
Uchoa, B.
Krüger, F.
contents We investigate the nature of the topological phase transition of the antiferromagnetic Kitaev model on the honeycomb lattice in the presence of a magnetic field along the [111] direction. The field opens a topological gap in the Majorana fermion spectrum and leads to a sequence of topological phase transitions before the field polarised state is reached. At mean field level the gap first closes at the three $M$ points in the Brillouin zone, where the Majorana fermions form Dirac cones, resulting in a change of Chern number by three. An odd number of Dirac fermions in the infrared is unusual and requires Berry curvature compensation in the UV, which occurs via topological, ring-like hybridisation gaps with higher-energy bands. We perform a renormalisation-group analysis of the topological phase transition at the three $M$ points within the Yukawa theory, allowing for intra- and inter-valley fluctuations of the spin-liquid bond operators. We find that the latter lead to a breaking of Lorentz invariance and hence a different universality compared to the standard Ising Gross-Neveu-Yukawa class.
format Preprint
id arxiv_https___arxiv_org_abs_2509_13057
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Nature of the Topological Transition of the Kitaev Model in [111] Magnetic Field
Thiagarajan, S.
Watson, C.
Yzeiri, T.
Hu, H.
Uchoa, B.
Krüger, F.
Strongly Correlated Electrons
Other Condensed Matter
We investigate the nature of the topological phase transition of the antiferromagnetic Kitaev model on the honeycomb lattice in the presence of a magnetic field along the [111] direction. The field opens a topological gap in the Majorana fermion spectrum and leads to a sequence of topological phase transitions before the field polarised state is reached. At mean field level the gap first closes at the three $M$ points in the Brillouin zone, where the Majorana fermions form Dirac cones, resulting in a change of Chern number by three. An odd number of Dirac fermions in the infrared is unusual and requires Berry curvature compensation in the UV, which occurs via topological, ring-like hybridisation gaps with higher-energy bands. We perform a renormalisation-group analysis of the topological phase transition at the three $M$ points within the Yukawa theory, allowing for intra- and inter-valley fluctuations of the spin-liquid bond operators. We find that the latter lead to a breaking of Lorentz invariance and hence a different universality compared to the standard Ising Gross-Neveu-Yukawa class.
title Nature of the Topological Transition of the Kitaev Model in [111] Magnetic Field
topic Strongly Correlated Electrons
Other Condensed Matter
url https://arxiv.org/abs/2509.13057