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Quantum phase transition in the Plaquette lattice with anisotropic spin exchange

Andreas Voigt
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Abstract

I study the influence of anisotropic spin exchange on a quantum phase transition in the Plaquette lattice driven by the purely quantum effect of singlet formation. I study the influence of i) a Dzyaloshinskii-Moriya exchange and ii) four spin exchange on the transition point by evaluating spin--spin correlations and the spin gap with exact diagonalization. The results point to a stabilization of the Neel-like long range order when the Dzyaloshinskii-Moriya exchange is added, whereas the four-spin exchange might stabilize the singlet order as well as the Neel-like order depending on its strength.

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Andreas Voigt. 2003-11-04. Quantum phase transition in the Plaquette lattice with anisotropic spin exchange. https://doi.org/10.1016/j.jmmm.2003.12.1145

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