Pseudogap and the Fermi surface in the t–J model Original Research Article

We calculate spectral functions within the t–J model as relevant to cuprates in the regime from low to optimum doping. On the basis of equations of motion for projected operators an effective spin–fermion coupling is derived. The self-energy due to short-wavelength transverse spin fluctuations is shown to lead to a modified self-consistent Born approximation, which can explain strong asymmetry between hole and electron quasiparticles. The coupling to long-wavelength longitudinal spin fluctuations governs the low-frequency behavior and results in a pseudogap behavior, which at low doping effectively truncates the Fermi surface.