Photoelectron Escape Depth and Inelastic Secondaries in High Temperature Superconductors

TL;DR

This paper calculates the photoelectron escape depth in Bi2212 high temperature superconductor and finds it to be very small, suggesting the background in photoemission is due to other factors.

Contribution

It provides a quantitative estimate of the escape depth and inelastic secondary electrons in high temperature superconductors using electron energy-loss spectroscopy data.

Findings

Escape depth is approximately 3 Å at typical photon energies.

Number of inelastic secondaries near the Fermi energy is small.

Large background in photoemission is likely due to other causes.

Abstract

We calculate the photoelectron escape depth in the high temperature superconductor Bi2212 by use of electron energy-loss spectroscopy data. We find that the escape depth is only 3 Ang. for photon energies typically used in angle resolved photoemission measurements. We then use this to estimate the number of inelastic secondaries, and find this to be quite small near the Fermi energy. This implies that the large background seen near the Fermi energy in photoemission measurements is of some other origin.