Effect of strong localization of doped holes in angle-resolved photoemission spectra of La$_{1-x}$Sr$_x$FeO$_3$

TL;DR

This study uses angle-resolved photoemission spectroscopy to investigate La$_{0.6}$Sr$_{0.4}$FeO$_3$, revealing strong hole localization effects and a pseudogap formation attributed to polaron-induced localization.

Contribution

First direct ARPES measurement of La$_{0.6}$Sr$_{0.4}$FeO$_3$ band structure showing hole localization and polaron effects.

Findings

Fe 3d bands shifted downward by ~1 eV from calculations

Formation of a ~1 eV pseudogap at the Fermi level

Strong localization of doped holes due to polaron formation

Abstract

We have performed an angle-resolved photoemission spectroscopy study of La$_{0.6}$Sr$_{0.4}$FeO$_3$ using {\it in situ} prepared thin films and determined its band structure. The experimental band dispersions could be well explained by an empirical band structure assuming the G-type antiferromagnetic state. However, the Fe 3d bands were found to be shifted downward relative to the Fermi level ($E_F$) by $\sim 1$ eV compared with the calculation and to form a (pseudo)gap of $\sim 1$ eV at $E_F$. We attribute this observation to a strong localization effect of doped holes due to polaron formation.