  
|
     
|
The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 5 Issue 3 (1998) pp 543-550
Mixed spin ladders with exotic ground states
A.K. Kolezhuk (a), H.-J. Mikeska
Institut für Theoretische Physik, Universität Hannover, Appelstrasse 2, 30167 Hannover, Germany
Received: 2 December 1997 / Accepted: 28 January 1998
Abstract: We study the "mixed spin" isotropic ladder system having S=1 spins on one leg and S=1/2 spins on the other, with general-type exchange interactions between spins on neighboring rungs. A set of model Hamiltonians with exact ground states in the form of a certain matrix product wave function is obtained. We show that sufficiently strong frustration can lead to exotic singlet ground states with infinite (exponential) degeneracy. We also list a couple of rather simple models with nontrivial ground states, including a model with only bilinear exchange.
PACS. 75.10.Jm Quantized spin models - 75.50.Ee Antiferromagnetics - 75.30.Kz Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.)
(a) Permanent address: Institute of Magnetism, 36(b) Vernadskii avenue, 252142 Kiev, Ukraine.email: kolezhuk@itp.uni-hannover.de
Article in PDF format (337 KB)
Online publication: October 26, 1998
LINK Helpdesk
© EDP Sciences, Springer-Verlag 1998