Fermi surface and spectral functions of a hole-doped spin-fermion model for cuprates - art. no. 214513

摘要

Using numerical techniques we study the spectral function A(k,omega) of a spin-fermion model for cuprates in the regime where magnetic and charge domains (stripes) are developed upon hole doping. From A(k,omega) we study the electronic dynamics and determine the Fermi surface (FS), which is compared with angular-resolved photoemission results for La2-xSrxCuO2. A pseudogap is observed in the density of states at the chemical potential for all finite dopings. The striped ground state appears to be metallic in this model since there is finite spectral weight at the chemical potential, but the electronic hopping seems to be stronger perpendicular to the stripes rather than along them. The band structure is not rigid, contrary to the behavior found in mean-field studies, and changes with doping. Both midgap (stripe-induced) and valence-band states determine the FS. For vertical (horizontal) stripes, a clear FS appears close to (pi ,0) [(0,pi)], while no FS is observed close to (0,pi) [(pi ,0)]. Along the diagonal direction the spectral function shows a clear quasiparticle peak close to (0,0), but its weight is reduced as the chemical potential is approached. A weak FS develops along this direction as the system is doped. [References: 33]