Excitation Spectrum for Quantum Spin Systems with Ladder, Plaquette and Mixed-Spin Structures

Akihisa Koga; Norio Kawakami

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arXiv · cond-mat/9908458

Excitation Spectrum for Quantum Spin Systems with Ladder, Plaquette and Mixed-Spin Structures

Akihisa Koga·Norio Kawakami

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Abstract

By using the series expansion techniques, we study the excitation spectrum for the two-dimensional quantum spin systems with ladder, plaquette and mixed-spin structures. We calculate the spin excitation gap and thus determine the phase boundary between the spin-gap phase and the magnetically ordered phase rather precisely. It is found that the phase diagram obtained improves fairly well the one previously obtained via the ground-state susceptibility.

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Akihisa Koga, Norio Kawakami. 1999-08-31. Excitation Spectrum for Quantum Spin Systems with Ladder, Plaquette and Mixed-Spin Structures. https://arxiv.org/abs/cond-mat/9908458

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