Photoemission studies of the near Fermi level spectral weight shifts in FeSe1-xTex superconductor

TL;DR

This study investigates how temperature affects the electronic structure of FeSe1-xTex superconductor, revealing a transition to an orbital selective Mott phase driven by structural changes.

Contribution

It demonstrates a temperature-induced crossover to an orbital selective Mott phase in FeSe1-xTex, linking structural changes to spectral weight shifts near the Fermi level.

Findings

Spectral weight transfer occurs near the Fermi level with temperature.

Structural changes induce shifts in orbital occupancy.

Evidence of a crossover to an orbital selective Mott phase.

Abstract

Our valence band photoelectron spectroscopic studies show a temperature dependent spectral weight transfer near the Fermi level in the Fe-based superconductor FeSe1-xTex. Using theoretical band structure calculations we have shown that the weight transfer is due to the temperature induced changes in the Fe(Se,Te)4 tetrahedra. These structural changes lead to shifts in the electron occupancy from the xz/yz and x2-y2 orbitals to the 3z2-r2 orbitals indicating a temperature induced crossover from a metallic state to an Orbital Selective Mott (OSM) Phase. Our study presents the observation of a temperature induced crossover to a low temperature OSM phase in the family of Fe chalcogenides.