Theory of angle-resolved photoemission experiments on a two-band model

TL;DR

This paper develops a theoretical framework for interpreting angle-resolved photoemission spectroscopy (ARPES) data on two-band models, emphasizing the importance of free electron states and the need for theoretical consistency.

Contribution

It introduces a formula for photoemission intensity considering electron states inside and outside the solid, providing a general method to analyze ARPES data.

Findings

Spectral function inside solids cannot be directly measured by ARPES.

Effects of free electron states significantly influence ARPES observations.

Theoretical calculations are essential for interpreting ARPES results accurately.

Abstract

Considering the electron states inside and outside the solid, we derive a formula of photoemission intensity. A general theoretical way to determine electronic structures of solids from ARPES experiments is outlined. It is shown that the spectral function inside the solids cannot be measured directly by ARPES, the effects of free electron states on the electronic structure observed by ARPES measurements must be considered, and the results from ARPES experiments cannot be understood until these results have been made consistent with a theoretical calculation.