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arXiv:cond-mat/0204539 · Physical review. B, Condensed matter

Density-matrix renormalization-group analysis of the spin- 12 XXZ chain in anXYsymmetric random magnetic field

Laura Urba, Anders Rosengren

Published Mar 14, 2003• 11 citations
arXivHTMLPDF

Abstract

The spin-$\frac{1}{2} \mathrm{XXZ}$ chain in a random magnetic field pointing in the Z direction is numerically studied using the density-matrix renormalization-group method. The phase diagram as a function of the anisotropy of the $\mathrm{XXZ}$ Hamiltonian and the strength of the random field is analyzed by computing the spin correlations and the superfluid density. To obtain the superfluid density we consider a superblock configuration representing a closed system with an arbitrary twist at the boundary. This allows us to estimate the size of the critical region where the quasi-long-range order persists, that is, where the spin correlation length is infinite and the superfluid density is nonzero.

DOI
10.1103/physrevb.67.104406

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