Coulomb Effects in Spectral Density and Transverse Conductivity of Layered Metals

Renormalization of the Coulomb interaction in layered metals results in a strongly anisotropic plasma mode with low frequencies for small components of wave vector in the in-plane direction. Interaction of electrons with this mode was found to lead to an incoherent contribution to the electron spectral density which spreads up to large energies. In the superconducting state this reproduces the peak-dip-hump feature similar to that observed in layered high-T$_c$ superconductors. The incoherent part of the spectral density and plasmon-assisted electron transitions provide mechanisms for nearly linear conductivity in the stack direction at large voltages or frequencies.
4 pages, 1 figure