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arXiv · 1907.11931

Magnetization plateau of the $S=2$ antiferromagnetic Heisenberg chain with anisotropies

Tôru Sakai·Kiyomi Okamoto·Takashi Tonegawa
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Abstract

We investigate the $S=2$ antiferromagnetic quantum spin chain with the exchange and single-ion anisotropies in a magnetic field, using the numerical exact diagonalization of finite-size clusters and the level spectroscopy analysis. It is found that a magnetization plateau possibly appears at a half of the saturation magnetization for some suitable anisotropy parameters. The level spectroscopy analysis indicates that the 1/2 magnetization plateau is formed by two different mechanisms, depending on the anisotropy parameters. The phase diagram of the 1/2 plateau states and some typical magnetization curves are also presented. In addition the biquadratic interaction is revealed to enhance the plateau induced by the Haldane mechanism.

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Tôru Sakai, Kiyomi Okamoto, Takashi Tonegawa. 2019-08-08. Magnetization plateau of the $S=2$ antiferromagnetic Heisenberg chain with anisotropies. https://doi.org/10.1103/physrevb.100.054407

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