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 q⃗=(2n,0)π for n≲0.5 , and at q⃗=(n,1)π 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 .