Dimensional crossover in alternating spin chains

Abstract

The effect of antiferromagnetic interchain coupling in alternating spin (1,1/2) chains is studied by mean of spin wave theory and density matrix renormalization group(DMRG). Two limiting cases are investigated, the two-leg ladder and its two dimensional (2D) generalization. For the 2D case, spin wave approximation predicts a smooth dimensional crossover keeping the ground state ordered, whereas in the ladder case the DMRG results show a gapped ground state for any $J_{\perp }>0$. Furthermore, the behavior of the correlation functions closely resemble the uniform spin-1/2 ladder. However, for small $J_{\perp }$, the gap behaves quadratically as $\Delta \sim 0.6J_{\perp }^2$. Similarly to uniform spin chains, it is conjectured an analogous spin gap behavior for an arbitrary number of mixed spin chains

3 pages, To appear in Physica B (Proceeding Fifth Latin American Workshop on Magnetism Magnetic Materials and their applications, LAW3M 2001)

References in corpus (1)

• Antiferromagnetically coupled alternating spin chains