Quantum phase transition in the random antiferromagnetic spin-1 chain

Citation
A. Saguia et al., Quantum phase transition in the random antiferromagnetic spin-1 chain, PHYS REV B, 62(9), 2000, pp. 5541-5545
Citations number
17
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B
ISSN journal
01631829 → ACNP
Volume
62
Issue
9
Year of publication
2000
Pages
5541 - 5545
Database
ISI
SICI code
0163-1829(20000901)62:9<5541:QPTITR>2.0.ZU;2-C
Abstract
We study the random antiferromagnetic spin-1 chain following the evolution of the bond probability distributions under a renormalization group transfo rmation. We use a mapping of the spin-1 chain into an effective spin-1/2 ch ain with both ferromagnetic (odd bonds) and antiferromagnetic (even and odd bonds) interactions. We obtain a recursion relation for the coupling const ants, solving exactly up to a four-spin cluster. Our improved perturbation treatment on these larger clusters shows that the random singlet phase in t he spin-1 chain, differently from previous results, is obtained only when 1 00% of the odd bonds are strong ferromagnetic, i.e., larger than the even a ntiferromagnetic bonds. Otherwise the ground state is that of a dimerized s pin-1/2 chain.