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We employ the phenomenological theory of the quasiparticle relaxation based on the simplified two-band description and the spin-fluctuation induced interband coupling to analyze recent normal-state transport data in electron-doped iron pnictides, in particular the Ba(Fe_1-x Co_x)_2As_2 family. Temperature dependence of the resistivity, thermopower and the Hall constant are evaluated. It is shown that their anomalous behavior emerging from experiments can be consistently described within the same framework assuming also non-Fermi-liquid spin fluctuations.
The Moris memory function approach to spin dynamics in doped antiferromagnetic insulator combined with the assumption of temperature independent static spin correlations and constant collective mode damping leads to w/T scaling in a broad range. The theory involving a nonuniversal scaling parameter is used to analyze recent inelastic neutron scattering results for underdoped cuprates. Adopting modified damping function also the emerging central peak in low-doped cuprates at low temperatures can be explained within the same framework.
The effect of a single static impurity on the many-body states and on the spin and thermal transport in the one-dimensional anisotropic Heisenberg chain at finite temperatures is studied. Whereas the pure Heisenberg model reveals Poisson level statis tics and dissipationless transport due to integrability, we show using the numerical approach that a single impurity induces Wigner-Dyson level statistics and at high enough temperature incoherent transport within the chain, whereby the relaxation time and d.c. conductivity scale linearly with length.
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