Magnetization Plateaux in Bethe Ansatz Solvable Spin-S Ladders
Abstract
We examine the properties of the Bethe Ansatz solvable two- and three-leg spin-
S
ladders. These models include Heisenberg rung interactions of arbitrary strength and thus capture the physics of the spin-
S
Heisenberg ladders for strong rung coupling. The discrete values derived for the magnetization plateaux are seen to fit with the general prediction based on the Lieb-Schultz- Mattis theorem. We examine the magnetic phase diagram of the spin-1 ladder in detail and find an extended magnetization plateau at the fractional value
<M>=1/2
in agreement with the experimental observation for the spin-1 ladder compound BIP-TENO.