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arXiv · 0806.2474

Low-lying excitations of the three-leg spin tube using the density-matrix renormalization group method

S. Nishimoto·M. Arikawa
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Abstract

Using the (dynamical) density-matrix renormalization group method, we study the low-energy physics of three-leg antiferromagnetic Heisenberg model where the periodic boundary conditions are applied in the rung direction. We confirm that the spin excitations are always gapped as long as the intra-ring couplings form a regular triangle. From precise finite-size-scaling analyses of the spin gap and dimerization order parameter, we also find that the spin gap is collapsed by very small asymmetric modulation of the intra-ring couplings. Moreover, the dynamical spin structure factors on the intra- and inter-leg correlations are calculated. It is demonstrated that the low-lying structure of the inter-leg spectra is particularly affected by the asymmetric modulation.

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S. Nishimoto, M. Arikawa. 2008-06-15. Low-lying excitations of the three-leg spin tube using the density-matrix renormalization group method. https://doi.org/10.1103/physrevb.78.054421

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