Marshall-Peierls Sign Rule in Frustrated Heisenberg Chains |

A. Voigt and J. RichterInstitut für Theoretische Physik, Otto-von-Guericke-Universität Magdeburg, Postfach 4120, 39106 Magdeburg, Germany |

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We consider the frustrated antiferromagnetic s=1 Heisenberg quantum spin chain with regard to the Marshall-Peierls sign rule. Using exact diagonalization data we investigate the breakdown of the Marshall- Peierls sign rule in dependence on frustration and compare our findings with data for s=1/2. We calculate a critical value of frustration J_{2}^{crit}, where the Marshall-Peierls sign rule is violated. The extrapolation of this value to the infinite chain limit holds J_{2}^{crit} ≈ 0.016, lower than in the case of s=1/2 (J_{2}^{crit} ≈ 0.027). T his points to a stronger influence of frustration in the case of s=1. Nevertheless, the calculation of the weight of the Ising-states violating the Marshall- Peierls sign rule shows that the latter holds approximately even for a quite large frustration and may be used for numerical techniques. |

DOI: 10.12693/APhysPolA.97.979 PACS numbers: 75.10.Jm, 75.40.Mg, 75.50.Ee |