Identification of a New Form of Electron Coupling in Bi2Sr2CaCu2O8 Superconductor by Laser-Based Angle-Resolved Photoemission

TL;DR

This study uses laser-based ARPES to discover new high-energy electron coupling features in a high-temperature superconductor, indicating a novel interaction mechanism beyond known phonon or magnetic modes.

Contribution

It reports the identification of previously unobserved high-energy features in the electron self-energy of Bi2Sr2CaCu2O8, suggesting a new form of electron coupling in high-Tc superconductors.

Findings

Discovery of high energy features at ~115 meV and ~150 meV in electron self-energy.

Features cannot be explained by known phonon or magnetic resonance modes.

Indication of a new electron coupling mechanism in high-temperature superconductors.

Abstract

Laser-based angle-resolved photoemission measurements with super-high resolution have been carried out on an optimally-doped Bi$_2$Sr$_2$CaCu$_2$O$_8$ high temperature superconductor. New high energy features at $\sim$115 meV and $\sim$150 meV, besides the prominent $\sim$70 meV one, are found to develop in the nodal electron self-energy in the superconducting state. These high energy features, which can not be attributed to electron coupling with single phonon or magnetic resonance mode, point to the existence of a new form of electron coupling in high temperature superconductors.