Study of Interacting Heisenberg Antiferromagnet Spin-1/2 and 1 Chains

Condensed Matter

article

Debasmita Maiti¹  Dayasindhu Dey¹  Manoranjan Kumar¹ 

[1] S. N. Bose National Centre for Basic Sciences

关键词: quantum phase transition;    Heisenberg antiferromagnetic;    density matrix renormalization group method;    ground-state properties;   

DOI  :  10.3390/condmat8010017

学科分类：社会科学、人文和艺术（综合）

来源: mdpi

【 摘 要 】

Haldane conjectures the fundamental difference in the energy spectrum of the Heisenberg antiferromagnetic (HAF) of the spin S chain is that the half-integer and the integer S chain have gapless and gapped energy spectrums, respectively. The ground state (gs) of the HAF spin-1/2 and spin-1 chains have a quasi-long-range and short-range correlation, respectively. We study the effect of the exchange interaction between an HAF spin-1/2 and an HAF spin-1 chain forming a normal ladder system and its gs properties. The inter-chain exchange interaction J ⊥ can be either ferromagnetic (FM) or antiferromagnetic (AFM). Using the density matrix renormalization group method, we show that in the weak AFM/FM coupling limit of J ⊥, the system behaves like two decoupled chains. However, in the large AFM J ⊥ limit, the whole system can be visualized as weakly coupled spin-1/2 and spin-1 pairs which behave like an effective spin-1/2 HAF chain. In the large FM J ⊥ limit, coupled spin-1/2 and spin-1 pairs can form pseudo spin-3/2 and the whole system behaves like an effective spin-3/2 HAF chain. We also derive the effective model Hamiltonian in both strong FM and AFM rung exchange coupling limits.

【 授权许可】

CC BY