Anisotropic Scattering and Anomalous Transport in a High Temperature Superconductor

TL;DR

This study reveals that in high-temperature cuprate superconductors, two distinct inelastic scattering channels influence transport properties, with one being highly anisotropic and linked to superconductivity, challenging existing theories.

Contribution

It introduces a novel magnetotransport method to distinguish scattering channels and shows the anisotropic scattering is connected to superconductivity in cuprates.

Findings

Two inelastic scattering channels identified in cuprates.

Anisotropic scattering correlates with superconductivity.

Heavily doped non-superconducting cuprates lack anisotropic scattering.

Abstract

The metallic state of high temperature cuprate superconductors is markedly different from that of textbook metals. The origin of this unconventional state, characterized by unusual and distinct temperature dependences in the transport properties, remains unresolved despite intense theoretical efforts. Our understanding is impaired by our inability to determine experimentally the temperature and momentum dependence of the transport scattering rate. Here we use a novel magnetotransport probe to show that the unusual temperature dependences of the resistivity and the Hall coefficient in highly doped Tl$_2$Ba$_2$CuO$_{6+\delta}$ originate from two distinct inelastic scattering channels. One channel is due to conventional electron-electron scattering whilst the other is highly anisotropic, has the same symmetry as the superconducting gap and a magnitude that grows approximately linearly with temperature. The observed form and anisotropy put tight constraints on theories of the metallic state. Moreover, in heavily doped non-superconducting cuprates, this anisotropic scattering term appears to be absent, suggesting an intimate connection between the origin of this scattering and superconductivity itself.