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Middle-Field Cusp Singularities in the Magnetization Process of One-Dimensional Quantum Antiferromagnets

Kouichi Okunishi·Yasuhiro Hieida·Yasuhiro Akutsu
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Abstract

We study the zero-temperature magnetization process (M-H curve) of one-dimensional quantum antiferromagnets using a variant of the density-matrix renormalization group method. For both the S=1/2 zig-zag spin ladder and the S=1 bilinear-biquadratic chain, we find clear cusp-type singularities in the middle-field region of the M-H curve. These singularities are successfully explained in terms of the double-minimum shape of the energy dispersion of the low-lying excitations. For the S=1/2 zig-zag spin ladder, we find that the cusp formation accompanies the Fermi-liquid to non-Fermi-liquid transition.

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Kouichi Okunishi, Yasuhiro Hieida, Yasuhiro Akutsu. 1999-04-20. Middle-Field Cusp Singularities in the Magnetization Process of One-Dimensional Quantum Antiferromagnets. https://doi.org/10.1103/physrevb.60.r6953

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