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Mixed spin ladders with exotic ground states

A. K. Kolezhuk·H. -J. Mikeska
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Abstract

We study the "mixed spin" isotropic ladder system having S=1 spins on one leg and S=1/2 spins on the other, with general-type exchange interactions between spins on neighboring rungs. A set of model Hamiltonians with exact ground states in the form of a certain matrix product wave function is obtained. We show that sufficiently strong frustration can lead to exotic singlet ground states with infinite (exponential) degeneracy. We also list a couple of rather simple models with nontrivial ground states, including a model with only bilinear exchange.

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A. K. Kolezhuk, H. -J. Mikeska. 1997-12-02. Mixed spin ladders with exotic ground states. https://doi.org/10.1007/s100510050475

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