c-axis optical conductivity in cuprates

We investigate the c-axis optical conductivity and DC resistivity of cuprat e superconductors in the normal state. Assuming that the interlayer hopping is incoherent vee express the conductivity with planar spectral functions obtained (i) from angle-resolved photoemission experiments (ARPES), (ii) us ing marginal Fermi liquid (MFL) ansatz, and (iii) with the finite-temperatu re Lanczos method for finite two-dimensional systems described by the t-J m odel. In the optimally doped regime anomalous relaxation rate tau(c)(-1) pr oportional to omega + xi(c)T found by Prelovsek et al. (Phys. Rev. Lett. 81 (1998) 3745) is analytically reproduced with the use of the marginal Fermi liquid ansatz for the self energy with parameters obtained from the exact diagonalization results. A semimetallic-like behavior of rho(c)(T) in the l ow doping regime emerges due to a pseudo-gap opening in the density of stat es. (C) 2000 Elsevier Science B.V. All rights reserved.