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Two-Dimensional Quantum Spin Systems with Ladder and Plaquette Structure

A. Koga·S. Kumada·N. Kawakami
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Abstract

We investigate low-energy properties of two-dimensional quantum spin systems with the ladder and plaquette structures, which are described by a generalized antiferromagnetic Heisenberg model with both of the bond and spin alternations. By exploiting a non-linear $σ$ model technique and a modified spin wave approach, we evaluate the spin gap and the spontaneous magnetization to discuss the quantum phase transition between the ordered and disordered states. We argue how the spin-gapped phase is driven to the antiferromagnetic phase in the phase diagram.

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A. Koga, S. Kumada, N. Kawakami. 1998-10-30. Two-Dimensional Quantum Spin Systems with Ladder and Plaquette Structure. https://doi.org/10.1143/jpsj.68.642

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