Orbital character variation of the Fermi surface and doping dependent changes of the dimensionality in BaFe2-xCoxAs2 from angle-resolved photoemission spectroscopy

TL;DR

This study uses ARPES and DFT to show how doping alters the orbital character and dimensionality of the Fermi surface in BaFe2-xCoxAs2, impacting magnetic and superconducting properties.

Contribution

It reveals doping-dependent changes in orbital character and dimensionality of the Fermi surface, linking electronic structure to phase behavior in BaFe2-xCoxAs2.

Findings

BaFe2As2 has mainly two-dimensional electronic states.

Co doping increases three-dimensionality of electronic states.

Orbital and dimensional changes affect nesting and phase transitions.

Abstract

From a combination of high resolution angle-resolved photoemission spectroscopy and density functional calculations, we show that BaFe2As2 possesses essentially two-dimensional electronic states, with a strong change of orbital character of two of the Gamma-centered Fermi surfaces as a function of kz. Upon Co doping, the electronic states in the vicinity of the Fermi level take on increasingly three-dimensional character. Both the orbital variation with kz and the more three-dimensional nature of the doped compounds have important consequences for the nesting conditions and thus possibly also for the appearance of antiferromagnetic and superconducting phases.