Momentum-Resolved Ultrafast Electron Dynamics in Superconducting Bi2Sr2CaCu2O8+delta

TL;DR

This study uses femtosecond time- and angle-resolved photoemission spectroscopy to investigate the ultrafast quasiparticle dynamics in a high-temperature superconductor, revealing momentum-dependent decay processes and a boson bottleneck effect.

Contribution

It provides new insights into the momentum-resolved quasiparticle decay mechanisms and the role of Cooper pair recombination in high-Tc superconductors.

Findings

Metastable quasiparticles detected near the antinode.

Decay through e-e scattering is momentum-dependent.

Relaxation dominated by Cooper pair recombination.

Abstract

The non-equilibrium state of the high-Tc superconductor Bi2Sr2CaCu2O8+delta and its ultrafast dynamics have been investigated by femtosecond time- and angle-resolved photoemission spectroscopy well below the critical temperature. We probe optically excited quasiparticles at different electron momenta along the Fermi surface and detect metastable quasiparticles near the antinode. Their decay through e-e scattering is blocked by a phase space restricted to the nodal region. The lack of momentum dependence in the decay rates is in agreement with relaxation dominated by Cooper pair recombination in a boson bottleneck limit.