UNIGE document Scientific Article
previous document  unige:87840  next document
add to browser collection
Title

Anomalous behavior of the spin gap of a spin-1/2 two-leg antiferromagnetic ladder with Ising-like rung interactions

Authors
Tonegawa, Takashi
Okamoto, Kiyomi
Sakai, Tôru
Published in Physica Status Solidi. B. 2013, vol. 250, no. 3, p. 575-578
Abstract Using mainly numerical methods, we investigate the width of the spin gap of a spin-1/2 two-leg ladder described by equation image, where equation image denotes the α-component of the spin-1/2 operator at the j-th site of the a (b) chain. We mainly focus on the equation image ≫ equation image and equation image case. The width of the spin gap between the M = 0 and 1 subspaces (M is the total magnetization) as a function of λ anomalously increases near λ = 0; for instance, for equation image ≲ equation image ≲ equation image when Jl/Jr = 0.1. The gap formation mechanism is thought to be different for the λ < 0 and λ > 0 cases. Since, in usual cases, the width of the gap becomes zero or small at the point where the gap formation mechanism changes, the above gap-increasing phenomenon in the present case is anomalous. We explain the origin of this anomalous phenomenon by use of the degenerate perturbation theory. We also draw the ground-state phase diagram.
Identifiers
Full text
Article (Published version) (352 Kb) - document accessible for UNIGE members only Limited access to UNIGE
Other version: http://doi.wiley.com/10.1002/pssb.201200757
Structures
Research group Groupe Giamarchi
Citation
(ISO format)
TONEGAWA, Takashi et al. Anomalous behavior of the spin gap of a spin-1/2 two-leg antiferromagnetic ladder with Ising-like rung interactions. In: Physica Status Solidi. B, 2013, vol. 250, n° 3, p. 575-578. https://archive-ouverte.unige.ch/unige:87840

74 hits

1 download

Update

Deposited on : 2016-09-28

Export document
Format :
Citation style :