Surface-driven electronic structure in LaFeAsO studied by angle resolved photoemission spectroscopy

TL;DR

This study uses ARPES to investigate the electronic structure of LaFeAsO, revealing surface-driven features and polarization effects that influence the observed electronic bands.

Contribution

It demonstrates that the large Gamma hole pocket observed in ARPES originates from surface effects, providing new insights into surface versus bulk electronic structures in LaFeAsO.

Findings

Large Gamma hole pocket is surface-derived.

Strong polarization dependence of band structure.

Temperature-dependent hole-like band at M point.

Abstract

We measured the electronic structure of an iron arsenic parent compound LaFeAsO using angle resolved photoemission spectroscopy (ARPES). By comparing with a full-potential Linear Augmented PlaneWave calculation we show that the extra large Gamma hole pocket measured via ARPES comes from electronic structure at the sample surface. Based on this we discuss the strong polarization dependence of the band structure and a temperature-dependent hole-like band around the M point. The two phenomena give additional evidences for the existence of the surface-driven electronic structure.