Origin of the photoemission final-state effects in Bi2Sr2CaCu2O8 by very-low-energy electron diffraction

TL;DR

This study uses very-low-energy electron diffraction and band calculations to analyze photoemission final states in Bi2Sr2CaCu2O8, revealing structured states, matrix effects, and extrinsic contributions affecting photoemission measurements.

Contribution

It provides detailed characterization of photoemission final states and demonstrates how diffraction effects influence photoemission results in Bi2Sr2CaCu2O8.

Findings

Structured final states explain matrix element effects.

Extrinsic contributions affect shadow Fermi surface.

Diffraction effects can tune photoemission experiments.

Abstract

Very-low-energy electron diffraction with a support of full-potential band calculations is used to achieve the energy positions, K// dispersions, lifetimes and Fourier compositions of the photoemission final states in Bi2Sr2CaCu2O8 at low excitation energies. Highly structured final states explain the dramatic matrix element effects in photoemission. Intense c(2x2) diffraction reveals a significant extrinsic contribution to the shadow Fermi surface. The final-state diffraction effects can be utilized to tune the photoemission experiment on specific valence states or Fermi surface replicas.