Orbitally resolved lifetimes in Ba(Fe0.92Co0.08)2As2 measured by ARPES

TL;DR

This study uses ARPES to resolve the orbital-dependent electron pocket structure in Ba(Fe0.92Co0.08)2As2, revealing differences in lifetimes between dxy and dxz/dyz orbitals that influence the material's electronic properties.

Contribution

It provides the first orbital-resolved measurement of electron pocket lifetimes in this compound, clarifying the orbital-specific roles in its electronic behavior.

Findings

dxy orbitals have longer lifetimes than dxz/dyz orbitals

Electron pockets are elliptically shaped and orbital-dependent

Orbital weight influences the ground state properties

Abstract

Despite many ARPES investigations of iron pnictides, the structure of the electron pockets is still poorly understood. By combining ARPES measurements in different experimental configurations, we clearly resolve their elliptic shape. Comparison with band calculation identify a deep electron band with the dxy orbital and a shallow electron band along the perpendicular ellipse axis with the dxz/dyz orbitals. We find that, for both electron and hole bands, the lifetimes associated with dxy are longer than for dxz/dyz. This suggests that the two types of orbitals play different roles in the electronic properties and that their relative weight is a key parameter to determine the ground state.