Quasiparticle band in the frustrated {ital t}-{ital t}{prime}-{ital J} model

We investigate the influence of frustration on the quasiparticle dispersion in the {ital t}-{ital J} and {ital t}-{ital t}{sup {prime}}-{ital J} models using the linear spin-wave theory and self-consistent Born approximation. The next-neighbor antiferromagnetic interactions, simulating the effect of doping within CuO{sub 2} planes of high-{ital T}{sub {ital c}} superconductors, lead to a drastic reduction of the quasiparticle bandwidth with the increasing frustration in a wide range of {ital t}, {ital t}{sup {prime}}, and {ital J} parameters. The low-energy quasiparticle band (with the width only {approximately}0.3 eV) obtained for the realistic values of parameters and a very weak quasiparticle state at the (0,0) point in the Brillouin zone agree quite well with the flat band observed at the Fermi level in the angle-resolved photoemission experiments for Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}. {copyright} {ital 1996 The American Physical Society.}