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The dynamical properties of a recently introduced phenomenological model
for high temperature superconductors are investigated. In the clean limit,
it was observed that none of the homogeneous or striped states that are
induced by the model at low temperatures can reproduce the recent
angle-resolved photoemission results for LSCO (Yoshida et al.,
Phys. Rev. Lett. 91, 027001 (2003)), that show a signal with two branches in
the underdoped regime. On the other hand, upon including quenched disorder
in the model and breaking the homogeneous state into "patches" that are
locally either superconducting or antiferromagnetic, the two-branch
spectra can be reproduced. In this picture, the nodal regions are
caused by d-wave superconducting clusters. Studying the density of
states (DOS), a pseudogap is observed, caused by the mixture of the gapped
antiferromagnetic state and a d-wave superconductor. The local DOS
can be interpreted using a two modes picture, similarly as observed in STM
experiments. It is concluded that a simple phenomenological model for
cuprates can capture many of the features observed in the underdoped
regime of these materials.
References: M. Mayr, G. Alvarez, A. Moreo, and E. Dagotto, cond-mat/0503727 G. Alvarez, M. Mayr, A. Moreo, and E. Dagotto, Phys. Rev. B 71, 014514 (2005) Y. Kohsaka et al., Phys. Rev. Lett. 93, 097004 (2004) |