Photoemission in the system of linear chains: Application to PrBa₂CU₃O₇ and La_2-x-yNd_ySr_xCuO₄

Photoemission in the system of linear charged chains has been studied within the one-step model incorporating the dipole transition matrix, from which its dependencies on the photoelectron momentum (k), photon polarization (Ê). and photon energy (ω) can be explored. The employed model is the three-dimensional array of noninteracting chains, which is so simple as to allow an analytic approach. Motivation of the study is for the doped CuO₃ chain in PrBa₂Cu₃O₇ and the doped static stripe phase in La_2-x-yNd_ySr_xCuO₄. From chains having one-dimensional dispersion exhibiting spin-charge separation, spectral dependences on the momentum perpendicular to the chain and photon polarization are discussed for PrBa₂Cu₃O₇. For La_2-x-yNd_ySr_xCuO₄, the anomalous spectral distribution formed by two sets of stripes perpendicular to each other is investigated. The geometric effects resulting from the transition matrix including the interference of photocurrents from different chains are found to change the simple one-dimensional feature drastically. We find these changes are consistent with experiment for the chain system PrBa₂Cu₃O₇, but less satisfactory for the stripe phase in La_2-x-yNd_ySr_xCuO₄. This means that in the stripe phase much two-dimensional character still exists unlike the chain system.