Relationship between doping-induced in-gap states and spin excitations in Kitaev-Hubbard models
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arXiv
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| Autores principales: | , , , |
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| Formato: | Preprint |
| Publicado: |
2026
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| _version_ | 1866913116506292224 |
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| author | Hou, Si-Qi Yu, Shun-Li Dong, Zhao-Yang Li, Jian-Xin |
| author_facet | Hou, Si-Qi Yu, Shun-Li Dong, Zhao-Yang Li, Jian-Xin |
| contents | We investigate the connection between doping-induced in-gap states and underlying spin excitations in Mott insulators by employing cluster perturbation theory on one-dimensional (1D) and quasi-1D Kitaev-Hubbard models. By manipulating Kitaev-like hopping terms ($t^{\prime}$) that selectively control spin anisotropies in the strong-coupling limit, we establish a direct correspondence between the kinetic dispersion of the in-gap states and the spin excitation spectra. Specifically, in the Z chain, in-gap states evolve from a gapless dispersion to a gapped flat band as the system transitions from the Heisenberg to the Ising model, exhibiting a gap scaling of $2t^{\prime 2}/U$ that matches the Ising spin gap. In the XY chain, the in-gap states split into a dispersive and a flat branch at the Kitaev limit, perfectly mirroring the Jordan-Wigner fermionic spectrum. For the two-leg ladder, we observe an emergent broad continuum of in-gap states that reflects the fractionalization of spin excitations, accompanied by a gap manifesting the presence of topological $Z_2$ visons. Our results establish a robust correspondence between charge and spin dynamics in doped Mott insulators and demonstrate that in-gap states can serve as a probe of exotic quantum spin phenomena, including fractionalization and topological excitations, offering a new pathway to investigate spin liquids via spectroscopic probes of charge excitations. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_11830 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Relationship between doping-induced in-gap states and spin excitations in Kitaev-Hubbard models Hou, Si-Qi Yu, Shun-Li Dong, Zhao-Yang Li, Jian-Xin Strongly Correlated Electrons We investigate the connection between doping-induced in-gap states and underlying spin excitations in Mott insulators by employing cluster perturbation theory on one-dimensional (1D) and quasi-1D Kitaev-Hubbard models. By manipulating Kitaev-like hopping terms ($t^{\prime}$) that selectively control spin anisotropies in the strong-coupling limit, we establish a direct correspondence between the kinetic dispersion of the in-gap states and the spin excitation spectra. Specifically, in the Z chain, in-gap states evolve from a gapless dispersion to a gapped flat band as the system transitions from the Heisenberg to the Ising model, exhibiting a gap scaling of $2t^{\prime 2}/U$ that matches the Ising spin gap. In the XY chain, the in-gap states split into a dispersive and a flat branch at the Kitaev limit, perfectly mirroring the Jordan-Wigner fermionic spectrum. For the two-leg ladder, we observe an emergent broad continuum of in-gap states that reflects the fractionalization of spin excitations, accompanied by a gap manifesting the presence of topological $Z_2$ visons. Our results establish a robust correspondence between charge and spin dynamics in doped Mott insulators and demonstrate that in-gap states can serve as a probe of exotic quantum spin phenomena, including fractionalization and topological excitations, offering a new pathway to investigate spin liquids via spectroscopic probes of charge excitations. |
| title | Relationship between doping-induced in-gap states and spin excitations in Kitaev-Hubbard models |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2605.11830 |