Spectral functions and the pseudogap in the t-J model - art. no. 180506

We calculate spectral functions within the t-J model as relevant to cuprate s in the regime from low to optimum doping. On the basis of equations of mo tion for projected operators an effective spin-fermion coupling is derived. The self-energy due to short-wavelength transverse spin fluctuations is sh own to lead to a modified self-consistent Born approximation, which can exp lain strong asymmetry between hole and electron quasiparticles. The couplin g to long-wavelength longitudinal spin fluctuations governs the low-frequen cy behavior and results in a pseudogap, which at low doping effectively tru ncates the Fermi surface, in particular near the (pi ,0) point in the Brill ouin zone.