c-axis Optical Conductivity in Cuprates

TL;DR

This paper studies the c-axis optical conductivity and resistivity in cuprate superconductors, using experimental data and theoretical models to understand the effects of doping and pseudogap formation on their electronic properties.

Contribution

It combines experimental spectral functions with theoretical models to analyze c-axis transport, revealing pseudogap effects and anomalous relaxation rates in cuprates.

Findings

Pseudogap causes semimetallic-like resistivity at low doping.

Anomalous relaxation rate observed in optimally doped regime.

Marginal Fermi liquid model reproduces key experimental features.

Abstract

We investigate the c-axis optical conductivity and d.c. resistivity of cuprate superconductors in the normal state. Assuming that the interlayer hopping is incoherent we express the conductivity with planar spectral functions obtained (i) from angle-resolved photoemission experiments, (ii) using marginal Fermi liquid ansatz, and (iii) with the finite-temperature Lanczos method for finite two-dimensional systems described by the t-J model. Here in the low doping regime a pseudo-gap opening in the density of states appears to be responsible for a semimetallic-like behavior of the D.C. resistivity. In the optimally doped regime we find an anomalous relaxation rate. Analytically this result is reproduced with the use of the marginal Fermi liquid ansatz for the self energy with parameters obtained from the exact diagonalization results.