Effect of thermal fluctuations of spin density wave order parameter on the quasiparticle spectral function

The two-dimensional model of itinerant electrons coupled to an antiferromagnetic order parameter is considered. In the mean-field solution the Fermi surface undergoes reconstruction and breaks into disconnected "pockets". We have studied the effect of the thermal fluctuations of the order parameter on the spectral density in such system. These fluctuations lead to a finite width of the spectral line scaling linearly with temperature. Due to the thermal fluctuations the quasiparticle spectral weight is transferred into a magnetic Brillouin zone. This can be interpreted as restoration of "arcs" of the noninteracting Fermi surface.