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Nonlinear sigma model study of a frustrated spin ladder

C. -M. Nedelcu·A. K. Kolezhuk·H. -J. Mikeska
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Abstract

A model of two-leg spin-S ladder with two additional frustrating diagonal exchange couplings J_{D}, J_{D}' is studied within the framework of the nonlinear sigma model approach. The phase diagram has a rich structure and contains 2S gapless phase boundaries which split off the boundary to the fully saturated ferromagnetic phase when J_{D} and J_{D}' become different. For the S=1/2 case, the phase boundaries are identified as separating two topologically distinct Haldane-type phases discussed recently by Kim et al. (cond-mat/9910023).

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C. -M. Nedelcu, A. K. Kolezhuk, H. -J. Mikeska. 1999-10-15. Nonlinear sigma model study of a frustrated spin ladder. https://doi.org/10.1088/0953-8984%2F12%2F6%2F317

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