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arXiv · 2501.11396

Band representations in Strongly Correlated Settings: The Kitaev Honeycomb Model

Axel Fünfhaus·Mikel García-Díez·M. G. Vergniory·Thilo Kopp·Stephen M. Winter·Roser Valentí
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Abstract

In the study of quantum spin liquids, the Kitaev model plays a pivotal role due to the fact that its ground state is exactly known as well as the fact that it may be realized in strongly frustrated materials such as $α$-RuCl${}_3$. While topological insulators and superconductors can be investigated by means of topological band theory -- in particular the topological quantum chemistry (TQC) formalism -- the Kitaev model evades such a treatment, as it is not possible to set up a proper single-particle Green's function for it. We instead associate spin operators with ``orbitals'' that give rise to a band structure. It is thereby possible to analyze the corresponding excitation spectrum engendered by these localized excitations by means of TQC. Special attention is given to the low-energy topological edge mode spectrum. Our work sheds light on the question how the TQC formalism may be generalized to strongly correlated and topologically ordered systems like the Kitaev model.

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Axel Fünfhaus, Mikel García-Díez, M. G. Vergniory, Thilo Kopp, Stephen M. Winter, Roser Valentí. 2025-05-10. Band representations in Strongly Correlated Settings: The Kitaev Honeycomb Model. https://arxiv.org/abs/2501.11396

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