Itinerancy and Electron Correlation in FeSe 1-x Superconductor Studied by Bulk-Sensitive Photoemission Spectroscopy

TL;DR

This study uses bulk-sensitive photoemission spectroscopy to analyze the electronic structure of FeSe1-x, revealing weak electron correlation and itinerant Fe 3d electrons, similar to other Fe-based high-temperature superconductors.

Contribution

It provides detailed experimental insights into the electronic structure and correlation effects in FeSe1-x, a newly discovered superconductor, using bulk-sensitive PES.

Findings

Large Fe 3d spectral weight near Fermi level

Narrowing of Fe 3d band width compared to calculations

Strong itinerant character of Fe 3d electrons

Abstract

We have investigated the electronic structures of newly discovered superconductor FeSe1-x by bulk-sensitive photoemission spectroscopy (PES). The large Fe 3d spectral weight is located in the vicinity of the Fermi level (EF) and it decreases steeply toward EF . Compared with results of band structure calculations, narrowing the Fe 3d band width and the energy shift of the band toward EF are found, suggesting a mass enhancement due to the weak electron correlation effect. Meanwhile, Fe 2p core-level PES reveals a strong itinerant character of Fe 3d electrons. These features are very similar to those in other Fe-based high-Tc superconductors.