### Abstract

We study the ground-state and finite-temperature properties of the one-dimensional isotropic spin-1/2 Heisenberg magnet with ferromagnetic nearest-neighbor and antiferromagnetic next-nearest-neighbor interactions which compete with each other. Extrapolating the exact results for finite-size systems of up to 20 spins, we estimate the ground-state energy and the ground-state two-spin correlation function in the infinite-size limit. Using the cluster transfer matrix method, we also calculate the temperature dependence of the internal energy and the specific heat and that of the inverse correlation length and the wave number, by both of which the asymptotic behavior of the two-spin correlation function in the long-distance limit is characterized. We compare the results of these calculations with those obtained previously for the case where the nearest-neighbor interaction is antiferromagnetic.

Original language | English |
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Pages (from-to) | 2902-2915 |

Number of pages | 14 |

Journal | Journal of the Physical Society of Japan |

Volume | 58 |

Issue number | 8 |

Publication status | Published - Aug 1989 |

Externally published | Yes |

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### Keywords

- Cluster transfer matrix method
- Competing interactions
- Exact diagonalization for finite-size systems
- Finite-temperature properties
- Ground-state properties
- One-dimensional system
- Spin-1/2 Heisenberg antiferromagnet

### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*Journal of the Physical Society of Japan*,

*58*(8), 2902-2915.