title: Nonanalytic spin susceptibility of a Fermi liquid: the case of Fe-based pnictides.
abstract: We propose an explanation of the peculiar linear temperature dependence of the uniform spin susceptibility chi(T) in ferropnictides. We argue that the linear in T term appears to be due to the nonanalytic temperature dependence of chi(T) in a two-dimensional Fermi liquid. We show that the prefactor of the T term is expressed via the square of the spin-density-wave (SDW) amplitude connecting nested hole and electron pockets. Because of an incipient SDW instability, this amplitude is large, which, along with a small value of the Fermi energy, makes the T dependence of chi(T) strong. We demonstrate that this mechanism is in quantitative agreement with the experiment.
authors: Max-Planck-Institut für Physik komplexer Systeme, D-01187 Dresden, Germany. maxim@mpipks-dresden.mpg.de
authors: M M
authors: MM
authors: Korshunov
authors: I
authors: I
authors: Eremin
authors: D V
authors: DV
authors: Efremov
authors: D L
authors: DL
authors: Maslov
authors: A V
authors: AV
authors: Chubukov