Spectral properties of nano-scale phase separate system



Within the framework of an approach which is a combination of the bond formalism and a method based on the spin polaron scenario we calculate the single-particle spectral function for the stripe system taking the form of two-leg ladder-like domain walls (DWs) between antiferromagnetic (AF) domains with the changing by π phase of the sublattice magnetization across each DW. We assume that singlets are formed on each rung belonging to the ladder-like DW, before the system is filled with holes. We analyze the doping level 1/8 and levels slightly above that value, which are interesting in the context of ARPES experiments in 214 systems. Neutron experiments indicate that the distance between stripe axes is 4 lattice spacings in this case. By comparing calculated and measured spectra we deduce that a different pattern of bond ordering in the stripe phase is most likely, namely the spin-Peierls state of parallel legs forming DWs which take the shape of two-leg ladders. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)