Spectral function and conductivity in the normal state of the cuprates: A spin fluctuation study - art. no. 020503

We study the spectral function A(k)(omega) and the optical conductivity sig ma (1)(omega) for a system of fermions interacting with their collective sp in fluctuations (the spin-fermion model), and apply the results to optimall y doped cuprates in the normal state. We show that there is no qualitative distinction between hot and cold regions in the Brillouin zone-in both case s, then exists a wide range of frequencies where the width of the peak in A (k)(omega) scales linearly with omega. We demonstrate that sigma (1)(omega) is inversely linear in omega up to very high frequencies. We argue that th e slopes of A(k)(omega) and sigma (1)(omega) agree quantitatively with the photoemission and optical data for Bi2212.