Linear temperature dependence of the spin susceptibility in Fe-pnictides.

We argue that linear $T$ dependence of the spin susceptibility $\chi >T$ observed in Fe pnictides can be explained within the itinerant Fermi liquid model of hole and electron bands. The spin susceptibility is linear in $T$ in a generic Fermi liquid in 2D. We show that for pnictides, the prefactor for the $T$ term comes chiefly from intra-band scattering and is strongly enhanced compared to an ordinary Fermi liquid as it contains precisely the same interaction that gives rise to spin-density-wave ordering. We compare theoretical slope with the data.