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Quantum Phase Transition of S=1/2 Trimerized XXZ Spin Chain in Magnetic Field

Kiyomi Okamoto·Atsuhiro Kitazawa
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Abstract

We study the magnetization plateau at a third of the saturation magnetization of the S=1/2 trimerized XXZ spin chain at T=0. The appearance of the plateau depends on the values of the XXZ anisotropy and the magnitude of the trimerization. This plateauful-plateauless transition is a quantum phase transition of the Berezinskii-Kosterlitz-Thouless type, which is difficult to precisely detect from the numerical data. To determine the phase boundary line of this transition precisely, we use the level crossing of low-lying excitations obtained from the numerical diagonalization. We also discuss the S=1/2 ferromagnetic-ferromagnetic-antiferromagnetic chain.

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Kiyomi Okamoto, Atsuhiro Kitazawa. 1999-07-30. Quantum Phase Transition of S=1/2 Trimerized XXZ Spin Chain in Magnetic Field. https://doi.org/10.1016/s0921-4526(99)01062-5

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