Diagonal bond ordered stripes in doped antiferromagnets: Stability analysis



Using a combination of the bond formalism and the recursion method we analyze the dynamics of a hole moving along a diagonal stripe which takes the shape of a slant stack formed by horizontal bonds which are in the spin singlet state. This work has been motivated by results of recent neutron scattering experiments on cuprates, suggesting the existence of bond order in the stripe phase which is a manifestation of the tendency towards nano-scale phase separation. The bond-ordered diagonal stripe separates antiferromagnetic domains with the opposite directions of the sublattice magnetization. The motion of a hole in the stripe is governed by the process of position exchange between the hole and the singlet on nearest bonds. Within a simplest approximation we assume that the hole propagation in 2D antiferromagnet is prevented by the string effect related to locally destroying the antiferromagnetic order by a hopping hole. In order to avoid this destruction the hole must return to the same point at which it has left the stripe. It must also retrace the same path along which it has entered the antiferromagnetic domain. We demonstrate that the diagonal stripe has higher energy than the horizontal stripe with bond order on legs, which provides additional confirmation of the suggestion that the scenario of bond-centered vertical and horizontal stripes with spin Peierls order on legs accounts for results of recent ARPES and neutron scattering measurements in 214 systems. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)