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Doping of an antiferromagnet with holes may lead to a spiral rearrangement
of the spins, as it has been argued by Shraiman and Siggia. The formation of
a spiral is consistent with the incommensurate magnetic order observed by
the neutron scattering experiments in the spin-glass phase of LSCO. The
spiral state has a chiral degeneracy that leads to the formation of
topologically nontrivial vortex-like defects. We propose that the
dissipative dynamics of these defects is responsible for the transport
properties in the spin-glass phase of cuprates[1,2]. Using the
collective-coordinate method, we show that the defects are coupled to a bath
of magnons. The resulting effective action, after the magnons have been
integrated out, indicates that the motion of the defects is damped due to
the scattering by the magnons. Assuming that the holes are attached to the
vortices, we have calculated the corresponding in-plane resistivity, which
exhibits an anisotropy and linear temperature dependence in agreement with
experimental data.
[1] V. Juricic, L. Benfatto, A. O. Caldeira, and C. Morais Smith, Phys. Rev. Lett. 92, 137202 (2004). [2] V. Juricic, L. Benfatto, A. O. Caldeira, and C. Morais Smith, Phys. Rev. B 71, 064421 (2005). |