Field-induced states and thermodynamics of the frustrated Heisenberg antiferromagnet on a square lattice
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arXiv
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| Format: | Preprint |
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2026
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| _version_ | 1866918342018727936 |
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| author | Honecker, Andreas Zhitomirsky, M. E. Wietek, Alexander Richter, Johannes |
| author_facet | Honecker, Andreas Zhitomirsky, M. E. Wietek, Alexander Richter, Johannes |
| contents | We investigate the ground-state and finite-temperature properties of the $J_1$-$J_2$ Heisenberg antiferromagnet on the square lattice in the presence of an external magnetic field. We focus on the highly frustrated regime around $J_2 \approx J_1/2$. The $h$-$T$ phase diagram is investigated with particular emphasis on the finite-temperature transition into the "up-up-up-down" state that is stabilized by thermal and quantum fluctuations and manifests itself as a plateau at one half of the saturation magnetization in the quantum case. We also discuss the enhanced magnetocaloric effect associated to the ground-state degeneracy that arises at the saturation field for $J_2=J_1/2$. For reference, we first study the classical case by classical Monte Carlo simulations. Then we turn to the extreme quantum limit of spin-1/2 where we perform zero- and finite-temperature Lanczos calculations. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2601_14380 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Field-induced states and thermodynamics of the frustrated Heisenberg antiferromagnet on a square lattice Honecker, Andreas Zhitomirsky, M. E. Wietek, Alexander Richter, Johannes Strongly Correlated Electrons We investigate the ground-state and finite-temperature properties of the $J_1$-$J_2$ Heisenberg antiferromagnet on the square lattice in the presence of an external magnetic field. We focus on the highly frustrated regime around $J_2 \approx J_1/2$. The $h$-$T$ phase diagram is investigated with particular emphasis on the finite-temperature transition into the "up-up-up-down" state that is stabilized by thermal and quantum fluctuations and manifests itself as a plateau at one half of the saturation magnetization in the quantum case. We also discuss the enhanced magnetocaloric effect associated to the ground-state degeneracy that arises at the saturation field for $J_2=J_1/2$. For reference, we first study the classical case by classical Monte Carlo simulations. Then we turn to the extreme quantum limit of spin-1/2 where we perform zero- and finite-temperature Lanczos calculations. |
| title | Field-induced states and thermodynamics of the frustrated Heisenberg antiferromagnet on a square lattice |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2601.14380 |