1 research outputs found
Antiferromagnetically coupled alternating spin chains
The effect of antiferromagnetic interchain coupling in alternating spin
(1,1/2) chains is studied by mean of a spin wave theory and density matrix
renormalization group (DMRG). In particular, two limiting cases are
investigated, the two-leg ladder and its two dimensional (2D) generalization.
Results of the ground state properties like energy, spin gap, magnetizations,
and correlation functions are reported for the whole range of the interchain
coupling . For the 2D case the spin wave results predict a smooth
dimensional crossover from 1D to 2D keeping the ground state always ordered.
For the ladder system, the DMRG results show that any drives the
system to a gapped ground state. Furthermore the behaviour of the correlation
functions closely resemble the uniform spin-1/2 ladder. For lower
than 0.3, however, the gap behaves quadratically as . Finally, it is argued that the behaviour of the spin gap for an
arbitrary number of mixed coupled spin chains is analogous to that of the
uniform spin-1/2 chains.Comment: 5 pages, 7 ps-figure