Momentum anisotropy of the scattering rate in cuprate superconductors

TL;DR

This study investigates the momentum and energy dependence of scattering rates in cuprate superconductors, revealing anisotropic elastic scattering linked to the pseudogap in underdoped samples, contrasting with isotropic scattering in overdoped samples.

Contribution

It provides new insights into the anisotropic scattering mechanisms and their relation to the pseudogap in cuprate superconductors using ARPES data.

Findings

Elastic scattering term 'a' is highly anisotropic in underdoped samples.

Inelastic coefficient 'b' is isotropic across doping levels.

Overdoped samples show isotropic scattering and no pseudogap above T_c.

Abstract

We examine the momentum and energy dependence of the scattering rate of the high temperature cuprate superconductors using angle resolved photoemission spectroscopy. The scattering rate is of the form a + bw around the Fermi surface for under and optimal doping. The inelastic coefficient "b" is found to be isotropic. The elastic term, "a", however, is found to be highly anisotropic for under and optimally doped samples, with an anisotropy which correlates with that of the pseudogap. This is contrasted with heavily overdoped samples, which show an isotropic scattering rate and an absence of the pseudogap above T_c. We find this to be a generic property for both single and double layer compounds.