Common Features in Electronic Structure of the Fe-Based Layered Superconductors from Photoemission Spectroscopy

TL;DR

This study uses high-resolution photoemission spectroscopy to identify common electronic structure features across Fe-based superconductors and their parent compounds, shedding light on their band structure and superconducting properties.

Contribution

The paper reveals universal electronic features in Fe-based superconductors, advancing understanding of their band structure and superconducting mechanisms.

Findings

Identification of a 0.2 eV feature in valence band

Universal 13-16 meV feature observed

Absence of superconducting coherence peaks

Abstract

High resolution photoemission measurements have been carried out on non-superconducting LaOFeAs parent compound and various superconducting R(O1-xFx)FeAs (R=La, Ce and Pr) compounds. We found that the parent LaOFeAs compound shows a metallic character. Through extensive measurements, we have identified several common features in the electronic structure of these Fe-based compounds: (1). 0.2 eV feature in the valence band; (2). A universal 13~16 meV feature; (3). A clear Fermi cutoff showing zero leading-edge shift in the superconducting state;(4). Lack of superconducting coherence peak(s); (5). Near EF spectral weight suppression with decreasing temperature. These universal features can provide important information about band structure, superconducting gap and pseudogap in these Fe-based materials.