Three-dimensional electronic structure of superconducting iron pnictides observed by angle-resolved photoemission spectroscopy

TL;DR

This study uses ARPES to explore the 3D electronic structure of iron pnictide superconductors, revealing doping-dependent Fermi surface changes and emphasizing the importance of orbital-dependent 3D effects in their magnetic and superconducting properties.

Contribution

First ARPES investigation showing the three-dimensional electronic structure and doping effects in iron pnictides, highlighting the significance of orbital-dependent 3D features.

Findings

Fermi surface sheets change with doping, showing hole pocket shrinkage and electron pocket expansion.

Band dispersions and Fermi surfaces are highly dependent on photon energy, indicating 3D electronic structure.

Orbital-dependent 3D electronic structure influences antiferromagnetism and superconductivity in pnictides.

Abstract

We have performed an angle-resolved photoemission spectroscopy (ARPES) study of the undoped and electron-doped iron pnictides BaFe2\_{-x}CoxAs2 (Ba122) (x=0, 0.14) and studied the Fermi surfaces (FSs) and band dispersions near the Fermi level. The FS sheets we observed are consistent with the shrinkage of the hole-like pockets around the Brillouin Zone (BZ) center and the expansion of the electron pockets around the BZ corner in the electron-doped compound as compared to the undoped parent compound. Band dispersions and FSs around the BZ center strongly depend on the photon energy, indicating the three-dimensional (3D) electronic structure. This observation suggests that the antiferromagnetism and superconductivity in the pnictides may have to be considered including the orbital-dependent 3D electronic structure, where FS nesting is not necessarily strong.