Dependence of angle-resolved photoemission spectra of high-temperature superconductors on the spin-fluctuation susceptibility

Angle-resolved photoemission-spectroscopy (ARPES) measurements on high-temperature superconductors, such as Bi-Sr-Ca-Cu-O, show three main components: these are a quasiparticle spectral peak that develops below the superconducting transition temperature T-c, an accompanying broad background of secondary electrons, and a dip feature beside the main quasiparticle peak. The broad background may originate from inelastic processes in which the photoelectron emits and absorbs spin fluctuations. Calculations of the quasiparticle spectral weight are presented incorporating these spin-fluctuation-mediated inelastic processes ill which the development of the superconducting gap Delta has been incorporated into the magnetic susceptibility chi(q,E). A dip feature develops below T-c in the quasiparticle spectral weight due to the shifting of spin-fluctuation spectral weight, Im chi(q,E), from low energies to energies greater than 2 Delta. These results provide evidence that the dip feature in the ARPES spectrum in high-temperature superconductors such as Bi-Sr-Ca-Cu-O is an opening of a spin gap below T-c.