### Abstract

The ground-state phase diagram of the S=1/2 XXZ ladder model is investigated by using the density-matrix renormalization-group method. This model is composed of two S=1/2 XXZ chains with ferromagnetic rung couplings (λ) and intra-chain anisotropy (Δ), and continuously changes from the two independent S=1/2 XXZ chains at λ=0 to the S=1 XXZ chain in the limit of λ→∞. It is shown that there exist edge states at Δ=1 and λ=1 in relation to the four-fold degeneracy of the ground state and that an excitation gap opens nearly at λ=0 for 0.8≤Δ≤1. In addition, it is clarified that the transition between the Haldane phase and the antiferromagnetic phase occurs at λ=1. 15±0.01 for Δ=1. A possible phase diagram in the λ-Δ plane is proposed, which is consistent with the scaling analysis based on the bosonization method.

Original language | English |
---|---|

Pages (from-to) | 4322-4330 |

Number of pages | 9 |

Journal | Journal of the Physical Society of Japan |

Volume | 64 |

Issue number | 11 |

Publication status | Published - 1995 Nov |

Externally published | Yes |

### Fingerprint

### Keywords

- Density-matrix renormalization-group method
- Haldane state
- S=1/2 XXZ ladder model

### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*Journal of the Physical Society of Japan*,

*64*(11), 4322-4330.

**Numerical study on the ground-state phase diagram of the S=1/2 XXZ ladder model.** / Narushima, Takeshi; Nakamura, Tota; Nakamura, Tota.

Research output: Contribution to journal › Article

*Journal of the Physical Society of Japan*, vol. 64, no. 11, pp. 4322-4330.

}

TY - JOUR

T1 - Numerical study on the ground-state phase diagram of the S=1/2 XXZ ladder model

AU - Narushima, Takeshi

AU - Nakamura, Tota

AU - Nakamura, Tota

PY - 1995/11

Y1 - 1995/11

N2 - The ground-state phase diagram of the S=1/2 XXZ ladder model is investigated by using the density-matrix renormalization-group method. This model is composed of two S=1/2 XXZ chains with ferromagnetic rung couplings (λ) and intra-chain anisotropy (Δ), and continuously changes from the two independent S=1/2 XXZ chains at λ=0 to the S=1 XXZ chain in the limit of λ→∞. It is shown that there exist edge states at Δ=1 and λ=1 in relation to the four-fold degeneracy of the ground state and that an excitation gap opens nearly at λ=0 for 0.8≤Δ≤1. In addition, it is clarified that the transition between the Haldane phase and the antiferromagnetic phase occurs at λ=1. 15±0.01 for Δ=1. A possible phase diagram in the λ-Δ plane is proposed, which is consistent with the scaling analysis based on the bosonization method.

AB - The ground-state phase diagram of the S=1/2 XXZ ladder model is investigated by using the density-matrix renormalization-group method. This model is composed of two S=1/2 XXZ chains with ferromagnetic rung couplings (λ) and intra-chain anisotropy (Δ), and continuously changes from the two independent S=1/2 XXZ chains at λ=0 to the S=1 XXZ chain in the limit of λ→∞. It is shown that there exist edge states at Δ=1 and λ=1 in relation to the four-fold degeneracy of the ground state and that an excitation gap opens nearly at λ=0 for 0.8≤Δ≤1. In addition, it is clarified that the transition between the Haldane phase and the antiferromagnetic phase occurs at λ=1. 15±0.01 for Δ=1. A possible phase diagram in the λ-Δ plane is proposed, which is consistent with the scaling analysis based on the bosonization method.

KW - Density-matrix renormalization-group method

KW - Haldane state

KW - S=1/2 XXZ ladder model

UR - http://www.scopus.com/inward/record.url?scp=21844499965&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=21844499965&partnerID=8YFLogxK

M3 - Article

VL - 64

SP - 4322

EP - 4330

JO - Journal of the Physical Society of Japan

JF - Journal of the Physical Society of Japan

SN - 0031-9015

IS - 11

ER -