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Néel and disordered phases of coupled Heisenberg chains with $S=1/2$ to S=4

S. Moukouri
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Abstract

We use the two-step density-matrix renormalization group method to study the effects of frustration in Heisenberg models for $S=1/2$ to S=4 in a two-dimensional anisotropic lattice. We find that as in $S=1/2$ studied previously, the system is made of nearly disconnected chains at the maximally frustrated point, $J_d/J_{\perp}=0.5$, i.e., the transverse spin-spin correlations decay exponentially. This leads to the following consequences: (i) all half-integer spins systems are gapless, behaving like a sliding Luttinger liquid as in $S=1/2$; (ii) for integer spins, there is an intermediate disordered phase with a spin gap, with the width of the disordered state is roughly proportional to the 1D Haldane gap.

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S. Moukouri. 2005-10-20. Néel and disordered phases of coupled Heisenberg chains with $S=1/2$ to S=4. https://doi.org/10.1088/1742-5468%2F2006%2F02%2Fp02002

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