Unmasking the nodal quasiparticle dynamics in cuprate superconductors using low-energy photoemission

TL;DR

This study uses high-resolution angle-resolved photoemission spectroscopy with tunable low-energy photons to investigate nodal quasiparticle dynamics in cuprate superconductors, revealing a suppressed scattering rate in the superconducting state and energy-dependent scattering behaviors.

Contribution

It uncovers the intrinsic single-particle scattering rate and bilayer splitting in Bi2Sr2CaCu2O8, providing new insights into quasiparticle scattering mechanisms in cuprates.

Findings

Nodal bilayer splitting is resolved using low-energy photons.

Scattering rate drops abruptly below the superconducting transition.

Energy dependence of scattering rates differs between bonding and antibonding bands.

Abstract

Nodal quasiparticles of Bi2Sr2CaCu2O8 have been studied by angle-resolved photoemission spectroscopy with high momentum and energy resolution. Low-energy tunable photons have enabled us to resolve a small nodal bilayer splitting, unmasking the intrinsic single-particle scattering rate. The nodal scattering rate is abruptly suppressed upon the superconducting transition, and shows a linear energy dependence at low energies, indicating the nontrivial effect of elastic scatterings on the quasiparticles. With increasing energy, the antibonding-band scattering rate becomes higher than the bonding one. The observations imply the character of the scatterers dominant at low energies.