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arXiv · 2411.09541

Magnetization process of a quasi-two-dimensional quantum magnet: Two-step symmetry restoration and dimensional reduction

Anneke Reinold·Lucas Berger·Marcin Raczkowski·Zhiying Zhao·Yoshimitsu Kohama·Masaki Gen·Denis I. Gorbunov·Yurii Skourski·Sergei Zherlitsyn·Fakher F. Assaad·Thomas Lorenz·Zhe Wang
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Abstract

We report on a comprehensive thermodynamic study of a quasi-two-dimensional (quasi-2D) quantum magnet Cu$_2$(OH)$_3$Br which in the 2D layer can be viewed as strongly coupled alternating antiferromagnetic and ferromagnetic chains. In an applied magnetic field transverse to the ordered spins below $T_N=9.3$ K, a field-induced phase transition from the 3D ordered to a disordered phase occurs at $B_c=16.3$ T for the lowest temperature, which is featured by an onset of a one-half plateau-like magnetization. By performing quantum Monte Carlo simulations of the relevant 2D model, we find that the plateau-like magnetization corresponds to a partial symmetry restoration and the full polarization in the ferromagnetic chains. Our numerical simulations also show that the magnetization saturation occurs with full symmetry restoration at a much higher field of $B_s \simeq 95$ T, corresponding to a 1D quantum phase transition in the antiferromagnetic chains. We argue that the experimentally observed field-induced phase transition at $B_c$ follows from the partial symmetry restoration and the concomitant dimensional reduction.

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Anneke Reinold, Lucas Berger, Marcin Raczkowski, Zhiying Zhao, Yoshimitsu Kohama, Masaki Gen, Denis I. Gorbunov, Yurii Skourski, Sergei Zherlitsyn, Fakher F. Assaad, Thomas Lorenz, Zhe Wang. 2024-11-14. Magnetization process of a quasi-two-dimensional quantum magnet: Two-step symmetry restoration and dimensional reduction. https://doi.org/10.1103/physrevb.111.l100405

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