Universality Classes of Diagonal Quantum Spin Ladders

Abstract

We find the classification of diagonal spin ladders depending on a characteristic integer $N_p$ in terms of ferrimagnetic, gapped and critical phases. We use the finite algorithm DMRG, non-linear sigma model and bosonization techniques to prove our results. We find stoichiometric contents in cuprate $Cu{O}_2$ planes that allow for the existence of weakly interacting diagonal ladders.

REVTEX4 file, 3 color figures, 1 table