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Striped phase in a quantum XY-model with ring exchange

A. W. Sandvik·S. Daul·R. R. P. Singh·D. J. Scalapino
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Abstract

We present quantum Monte Carlo results for a square-lattice S=1/2 XY-model with a standard nearest-neighbor coupling J and a four-spin ring exchange term K. Increasing K/J, we find that the ground state spin-stiffness vanishes at a critical point at which a spin gap opens and a striped bond-plaquette order emerges. At still higher K/J, this phase becomes unstable and the system develops a staggered magnetization. We discuss the quantum phase transitions between these phases.

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A. W. Sandvik, S. Daul, R. R. P. Singh, D. J. Scalapino. 2002-12-02. Striped phase in a quantum XY-model with ring exchange. https://doi.org/10.1103/physrevlett.89.247201

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