| Within a variational approach based on the so called string scenario for doped antiferromagnets we analyze in the framework of the t-t'-t"-J model the formation of spin polarons with different symmetries which are related to the representations of the point group for the square lattice. Our goal is to understand the origin of the high-energy anomaly seen in angle resolved photoemission spectra of cuprates. Due to the exchange energy increase induced by the creation of fluctuations during hole hopping, wave functions of spin polarons which represent holes doped into the antiferromagnet and dressed in spin fluctuations are confined to regions around some lattice sites. Low energy spin polarons may have s-wave, d-wave and p-wave symmetry. Quasiparticle propagation of holes is enabled by some high order processes. Those processes induce the hybridization of spin polarons, which gives rise in the nominally single band model to a multiband-like electronic structure resembling the structure of multiorbital systems. Along the (π/2,π/2)-(0,0) line the highest spectral weight posses a band located nearest to the Fermi energy with a high contribution from s-wave polarons and a band with a high contribution from p-wave polarons, which suggests a close relation between the high-energy anomaly and the so called mid-infrared band observed in the spectra of optical conductivity. The distribution of spectral weight between different bands is governed by the coupling, during the hole-removal process, between states representing local fluctuations in the AF background and so called string states formed when a hole starts to hop in such a background. |
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