Coupling of Low Energy Electrons in Optimally Doped Bi2212 to an Optical Phonon Mode

TL;DR

This study uses laser photoemission to investigate low energy electron behavior in optimally doped Bi2212, revealing a dispersion kink linked to an optical phonon, confirmed through experimental and theoretical scattering rate comparisons.

Contribution

It identifies and confirms the coupling of low energy electrons to a specific optical phonon mode in Bi2212 using combined experimental and theoretical analysis.

Findings

Observation of a dispersion kink near the Fermi energy.

Confirmation of phonon-electron coupling through scattering rate analysis.

Identification of the phonon mode consistent with Raman studies.

Abstract

Laser based photoemission with photons of energy 6 eV is used to examine the fine details of the very low energy electron dispersion and associated dynamics in the nodal region of optimally doped Bi2212. A "kink" in the dispersion in the immediate vicinity of the Fermi energy is associated with scattering from an optical phonon previously identified in Raman studies. The identification of this phonon as the appropriate mode is confirmed by comparing the scattering rates observed experimentally with the results of calculated scattering rates based on the properties of the phonon mode.