Effect of a Normal-State Pseudogap on Optical Conductivity in Underdoped Cuprate Superconductors

Abstract

We calculate the c-axis infrared conductivity ${\sigma }_c(\omega )$ in underdoped cuprate superconductors for spinfluctuation exchange scattering within the CuO${}_2$-planes including a phenomenological d-wave pseudogap of amplitude $E_g$. For temperatures decreasing below a temperature $T^{\ast }\sim E_g/2$, a gap for $\omega <2E_g$ develops in ${\sigma }_c(\omega )$ in the incoherent (diffuse) transmission limit. The resistivity shows 'semiconducting' behavior, i.e. it increases for low temperatures above the constant behavior for $E_g=0$. We find that the pseudogap structure in the in-plane optical conductivity is about twice as big as in the interplane conductivity ${\sigma }_c(\omega )$, in qualitative agreement with experiment. This is a consequence of the fact that the spinfluctuation exchange interaction is suppressed at low frequencies as a result of the opening of the pseudogap. While the c-axis conductivity in the underdoped regime is described best by incoherent transmission, in the overdoped regime coherent conductance gives a better description.

to be published in Phys. Rev. B (November 1, 1999)

References in corpus (3)

• Measurement of an Anisotropic Energy Gap in Single Plane Bi_2Sr_(2-x)La_xCuO_(6+d)
• Temperature Evolution of the Pseudogap State in the Infra-Red Response of Underdoped La_(2-x)Sr_xCuO_4
• c-axis conductivity in the normal state of cuprate superconductors

Cited by in corpus (1)

• Theory on Superconducting Transition from Pseudogap State