Spin and charge gaps of the half-filled N-leg Kondo ladders

In this work, we study N-leg Kondo ladders at half-filling through the density matrix renormalization group. We found nonzero spin and charge gaps for any finite number of legs and Kondo coupling J>0. We also show evidence of the existence of a quantum critical point in the two-dimensional Kondo lattice model, in agreement with previous works. Based on the binding energy of two holes, we did not find evidence of superconductivity in the two-dimensional Kondo lattice model close to half filling.681