Experimental investigation of the electronic structure of Ca$_{0.83}$La$_{0.17}$Fe$_2$As$_2$

TL;DR

This study combines ARPES and STM techniques to explore the electronic structure of electron-doped Ca$_{0.83}$La$_{0.17}$Fe$_2$As$_2$, revealing surface reconstruction, band folding, and a possible superconducting gap-like feature.

Contribution

It provides new insights into the surface reconstruction and electronic structure of Ca$_{0.83}$La$_{0.17}$Fe$_2$As$_2$, highlighting similarities with other iron-based superconductors.

Findings

Surface reconstruction associated with As dimerization observed.

Fermi surface topology similar to BaFe$_{1.85}$Co$_{0.15}$As$_2$.

A gap-like density of states depression of 7.7 meV detected.

Abstract

We performed a combined angle-resolved photoemission spectroscopy and scanning tunneling microscopy study of the electronic structure of electron-doped Ca$_{0.83}$La$_{0.17}$Fe$_2$As$_2$. A surface reconstruction associated with the dimerization of As atoms is observed directly in the real space, as well as the consequent band folding in the momentum space. Besides this band folding effect, the Fermi surface topology of this material is similar to that reported previously for BaFe$_{1.85}$Co$_{0.15}$As$_2$, with $\Gamma$-centred hole pockets quasi-nested to M-centred electron pockets by the antiferromagnetic wave vector. Although no superconducting gap is observed by ARPES possibly due to low superconducting volume fraction, a gap-like density of states depression of $7.7\pm 2.9$ meV is determined by scanning tunneling microscopy.