Phase diagram of the two-leg Kondo ladder

The phase diagram of the two-leg Kondo ladder is investigated using computational techniques. Ferromagnetism is present, but only at small conduction electron densities and robust Kondo coupling J. For densities n*0.4 and any Kondo coupling, a paramagnetic phase is found. We also observed spin dimerization at densities n=1/4 and n=1/2. The spin-structure factor at small J peaks at qW = s2n ,0dp for n&0.5, and at qW = sn ,1dp for n*0.5. The charge structure factor suggests that electrons behave as free particles with spin -1 /2 (spin-0) for small (large) J.