Electron Removal Self Energy and its application to Ca2CuO2Cl2

TL;DR

This paper introduces a method to extract the electron removal self energy from ARPES data, applicable to non-quasiparticle spectral functions, and applies it to Ca2CuO2Cl2 revealing weak k-dependence and high energy features.

Contribution

It develops a new approach to obtain the removal self energy in full k-omega space without assuming momentum independence, applied to cuprate ARPES data.

Findings

Self energy is weakly k-dependent in Ca2CuO2Cl2.

Maximum of Im Sigma occurs around 1 eV, indicating a high energy kink.

Method aligns with peak width analysis of spectral features.

Abstract

We propose using the self energy defined for the electron removal Green's function. Starting from the electron removal Green's function, we obtained expressions for the removal self energy Sigma^ER (k,omega) that are applicable for non-quasiparticle photoemission spectral functions from a single band system. Our method does not assume momentum independence and produces the self energy in the full k-omega space. The method is applied to the angle resolved photoemission from Ca_2CuO_2Cl_2 and the result is found to be compatible with the self energy value from the peak width of sharp features. The self energy is found to be only weakly k-dependent. In addition, the Im Sigma shows a maximum at around 1 eV where the high energy kink is located.