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arXiv · 2201.02171

Thermal Ising transition in the spin-1/2 J1-J2 Heisenberg model

Olivier Gauthé·Frédéric Mila
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Abstract

Using an SU(2) invariant finite-temperature tensor network algorithm, we provide strong numerical evidence in favor of an Ising transition in the collinear phase of the spin-1/2 $J_1-J_2$ Heisenberg model on the square lattice. In units of $J_2$, the critical temperature reaches a maximal value of $T_c/J_2\simeq 0.18$ around $J_2/J_1\simeq 1.0$. It is strongly suppressed upon approaching the zero-temperature boundary of the collinear phase $J_2/J_1\simeq 0.6$, and it vanishes as $1/\log(J_2/J_1)$ in the large $J_2/J_1$ limit, as predicted by Chandra, Coleman and Larkin [Phys. Rev. Lett. 64, 88, 1990]. Enforcing the SU(2) symmetry is crucial to avoid the artifact of finite-temperature SU(2) symmetry breaking of U(1) algorithms, opening new perspectives in the investigation of the thermal properties of quantum Heisenberg antiferromagnets.

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Olivier Gauthé, Frédéric Mila. 2022-01-06. Thermal Ising transition in the spin-1/2 J1-J2 Heisenberg model. https://doi.org/10.1103/physrevlett.128.227202

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