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EnglishWe study finite-temperature topological properties of the Kitaev’s spin-honeycomb model in the vortex-free sector with the use of the recently introduced mean Uhlmann curvature. We employ an appropriate fermionization procedure to study the system as a two-band p-wave superconductor described by a Bogoliubov–de Gennes Hamiltonian. This allows us to study relevant quantities such as Berry and mean Uhlmann curvatures in a simple setting. More specifically, we consider the spin honeycomb in the presence of an external magnetic field breaking time-reversal symmetry. The introduction of such an external perturbation opens up a gap in the phase of the system characterized by non-Abelian statistics. The resulting model belongs to a symmetry-protected class, so that the Uhlmann number can be analyzed. We first consider the Berry curvature on a particular evolution line over the phase diagram. The mean Uhlmann curvature and the Uhlmann number are then analyzed by assuming a thermal state. The mean Uhlmann curvature describes a crossover effect as temperature rises. In the trivial phase, a nonmonotonic dependence of the Uhlmann number, as temperature increases, is reported and explained.
| Data di pubblicazione: | 2019 |
| Titolo: | Finite-temperature geometric properties of the Kitaev honeycomb model |
| Autori: | |
| Citazione: | Bascone, F., Leonforte, L., Valenti, D., Spagnolo, B., & Carollo, A. (2019). Finite-temperature geometric properties of the Kitaev honeycomb model. PHYSICAL REVIEW. B, 99(20), 205155-1-205155-10. |
| Rivista: | |
| Digital Object Identifier (DOI): | 10.1103/PhysRevB.99.205155 |
| Abstract: | We study finite-temperature topological properties of the Kitaev’s spin-honeycomb model in the vortex-free sector with the use of the recently introduced mean Uhlmann curvature. We employ an appropriate fermionization procedure to study the system as a two-band p-wave superconductor described by a Bogoliubov–de Gennes Hamiltonian. This allows us to study relevant quantities such as Berry and mean Uhlmann curvatures in a simple setting. More specifically, we consider the spin honeycomb in the presence of an external magnetic field breaking time-reversal symmetry. The introduction of such an external perturbation opens up a gap in the phase of the system characterized by non-Abelian statistics. The resulting model belongs to a symmetry-protected class, so that the Uhlmann number can be analyzed. We first consider the Berry curvature on a particular evolution line over the phase diagram. The mean Uhlmann curvature and the Uhlmann number are then analyzed by assuming a thermal state. The mean Uhlmann curvature describes a crossover effect as temperature rises. In the trivial phase, a nonmonotonic dependence of the Uhlmann number, as temperature increases, is reported and explained. |
| URL: | https://journals.aps.org/prb/abstract/10.1103/PhysRevB.99.205155 |
| Settore Scientifico Disciplinare: | Settore FIS/03 - Fisica Della Materia |
| Appare nelle tipologie: | 1.01 Articolo in rivista |
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| File | Descrizione | Tipologia | Licenza | |
|---|---|---|---|---|
| Phys_Rev_B_99_205155_2019.pdf | Articolo completo | Versione Editoriale | Open Access Visualizza/Apri |
http://hdl.handle.net/10447/360546
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