Zero energy Majorana modes in spin ladders and a possible realization of   the Kitaev model
  We show that in double-chain Mott insulators (ladders), disordered alternating ionic potentials may locally destroy coherence of magnetic excitations and lead to the appearance of spontaneously dimerized islands inside the Haldane spin-liquid phase. We argue that a boundary between the dimerized and Haldane phases of a spin-1/2 ladder supports a localized zero-energy Majorana fermion mode. Based on these findings we suggest a realization of a generalized Kitaev model where Majorana fermions can propagate in more than one dimension. 
A. A. Nersesyan and A. M. Tsvelik
cond-mat.str-el cond-mat.mes-hall quant-ph