Nonanalytic Spin Susceptibility of a Fermi Liquid: The Case of Fe-Based Pnictides

Max-Planck-Institut für Physik komplexer Systeme, D-01187 Dresden, Germany.
Physical Review Letters (Impact Factor: 7.51). 07/2009; 102(23):236403. DOI: 10.1103/PhysRevLett.102.236403
Source: PubMed


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.

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