Eur. Phys. J. B 57, 265-270 (2007)
https://doi.org/10.1140/epjb/e2007-00180-9

Phase diagram of frustrated mixed-spin ladders in the strong-coupling limit

Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100080, P.R. China

Corresponding author: ^a schen@aphy.iphy.ac.cn

Received: 15 December 2006
Revised: 16 April 2007
Published online: 22 June 2007

Abstract

We study the ground-state properties of frustrated Heisenberg ferrimagnetic ladders with antiferromagnetic exchange interactions and two types of alternating sublattice spins. In the limit of strong rung couplings, we show that the mixed spin-1/2 and spin-1 ladders can be systematically mapped onto a spin-1/2 Heisenberg model with additional next-nearest-neighbor exchanges. The system is either in a ferrimagnetic state or in a critical spin-liquid state depending on the competition between the spin exchanges along the legs and the diagonal exchanges.