Thermal decay of two-spinon bound states in quasi-2D triangular antiferromagnets
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| Format: | Preprint |
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2024
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| author | Pomponio, I. L. Ghioldi, E. A. Gazza, C. J. Manuel, L. O. Trumper, A. E. |
| author_facet | Pomponio, I. L. Ghioldi, E. A. Gazza, C. J. Manuel, L. O. Trumper, A. E. |
| contents | We analyze the temperature evolution of the anomalous magnetic spectrum of the spin-1/2 triangular quantum Heisenberg antiferromagnet, which is proximate to a quantum phase transition leading to a spin liquid phase. Recently, its low energy excitations have been identified with two-spinon bound states, well defined in an ample region of the Brillouin zone. In this work, we compute the thermal magnetic spectrum within a Schwinger boson approach, incorporating Gaussian fluctuations around the saddle-point approximation. In order to account for a finite Néel temperature $T_N$, we incorporate an exchange interaction between triangular layers. As temperature rises, the dispersion relation of the two-spinon bound states, representing single-magnon excitations, remains unchanged but becomes mixed with the thermally activated spinon continuum. Consequently, a crossover occurs at a temperature $T^* \simeq 0.75 T_N$, defining a {\it terminated Goldstone regime} between $T^*$ and $T_N$, where only the magnons close to the Goldstone modes survive as well-defined excitations, up to the Néel temperature. Our results support the idea that the fractionalization of magnons near a transition to a disordered phase can be extended to more realistic quasi-2D frustrated antiferromagnets. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2406_17165 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Thermal decay of two-spinon bound states in quasi-2D triangular antiferromagnets Pomponio, I. L. Ghioldi, E. A. Gazza, C. J. Manuel, L. O. Trumper, A. E. Strongly Correlated Electrons We analyze the temperature evolution of the anomalous magnetic spectrum of the spin-1/2 triangular quantum Heisenberg antiferromagnet, which is proximate to a quantum phase transition leading to a spin liquid phase. Recently, its low energy excitations have been identified with two-spinon bound states, well defined in an ample region of the Brillouin zone. In this work, we compute the thermal magnetic spectrum within a Schwinger boson approach, incorporating Gaussian fluctuations around the saddle-point approximation. In order to account for a finite Néel temperature $T_N$, we incorporate an exchange interaction between triangular layers. As temperature rises, the dispersion relation of the two-spinon bound states, representing single-magnon excitations, remains unchanged but becomes mixed with the thermally activated spinon continuum. Consequently, a crossover occurs at a temperature $T^* \simeq 0.75 T_N$, defining a {\it terminated Goldstone regime} between $T^*$ and $T_N$, where only the magnons close to the Goldstone modes survive as well-defined excitations, up to the Néel temperature. Our results support the idea that the fractionalization of magnons near a transition to a disordered phase can be extended to more realistic quasi-2D frustrated antiferromagnets. |
| title | Thermal decay of two-spinon bound states in quasi-2D triangular antiferromagnets |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2406.17165 |