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| Autori principali: | , , , , , , , , |
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| Natura: | Preprint |
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2025
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| Accesso online: | https://arxiv.org/abs/2511.17381 |
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| _version_ | 1866908669017325568 |
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| author | Ranjith, K. M. Dupont, Maxime Krämer, Steffen Capponi, Sylvain Orignac, Edmond Laflorencie, Nicolas Kurita, Nobuyuki Tanaka, Hidekazu Horvatić, Mladen |
| author_facet | Ranjith, K. M. Dupont, Maxime Krämer, Steffen Capponi, Sylvain Orignac, Edmond Laflorencie, Nicolas Kurita, Nobuyuki Tanaka, Hidekazu Horvatić, Mladen |
| contents | We study the spin dynamics in the quasi-2D spin-$1/2$ dimer compound Ba$_2$CuSi$_2$O$_6$Cl$_2$, which exhibits a magnetic field-induced Bose-Einstein condensate (BEC) of triplons. Using nuclear magnetic resonance (NMR) spin-lattice relaxation rate ($T_1^{-1}$) measurements combined with large-scale quantum Monte Carlo (QMC) simulations, we investigate critical fluctuations across the field-temperature phase diagram. Bridging the behavior observed in 1D and 3D systems, the $T_1^{-1}$ relaxation rate shows a pronounced peak extending well above the Néel temperature $T_N$, indicating strong two-dimensional Berezinskii-Kosterlitz-Thouless (BKT)-type fluctuations. A quantitative match between experimental and theoretical BEC phase boundaries validates an effective XXZ model. The study determines the intrinsic BKT transition temperature $T_{\mathrm{BKT}}$ from QMC, revealing a nearly field-independent $T_{\mathrm{BKT}}/T_N \approx 0.74$. Scaling analysis of the relaxation rate shows critical exponents consistent with 2D universality, and a narrow temperature window is identified where 2D physics dominates. These findings establish Ba$_2$CuSi$_2$O$_6$Cl$_2$ as a model system for exploring BKT dynamics in quantum magnets. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_17381 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Critical BKT dynamics in the archetypal 2D spin system Ba$_2$CuSi$_2$O$_6$Cl$_2$ Ranjith, K. M. Dupont, Maxime Krämer, Steffen Capponi, Sylvain Orignac, Edmond Laflorencie, Nicolas Kurita, Nobuyuki Tanaka, Hidekazu Horvatić, Mladen Strongly Correlated Electrons We study the spin dynamics in the quasi-2D spin-$1/2$ dimer compound Ba$_2$CuSi$_2$O$_6$Cl$_2$, which exhibits a magnetic field-induced Bose-Einstein condensate (BEC) of triplons. Using nuclear magnetic resonance (NMR) spin-lattice relaxation rate ($T_1^{-1}$) measurements combined with large-scale quantum Monte Carlo (QMC) simulations, we investigate critical fluctuations across the field-temperature phase diagram. Bridging the behavior observed in 1D and 3D systems, the $T_1^{-1}$ relaxation rate shows a pronounced peak extending well above the Néel temperature $T_N$, indicating strong two-dimensional Berezinskii-Kosterlitz-Thouless (BKT)-type fluctuations. A quantitative match between experimental and theoretical BEC phase boundaries validates an effective XXZ model. The study determines the intrinsic BKT transition temperature $T_{\mathrm{BKT}}$ from QMC, revealing a nearly field-independent $T_{\mathrm{BKT}}/T_N \approx 0.74$. Scaling analysis of the relaxation rate shows critical exponents consistent with 2D universality, and a narrow temperature window is identified where 2D physics dominates. These findings establish Ba$_2$CuSi$_2$O$_6$Cl$_2$ as a model system for exploring BKT dynamics in quantum magnets. |
| title | Critical BKT dynamics in the archetypal 2D spin system Ba$_2$CuSi$_2$O$_6$Cl$_2$ |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2511.17381 |