2008/06/20 by V. Vildosola, Veronica Vildosola, Leonid V. Pourovskii +4 · 2 citations
Chemistry · Materials Science · Physics and Astronomy · #Chemistry #Condensed matter physics #Electronic band structure #Electronic structure #Fermi surface #Iron-based superconductors research #Materials science #Physics #Pnictogen #Quasiparticle #Superconductivity #cond-mat.mtrl-sci #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.78.064518
published as Phys. Rev. B 78, 064518 (2008) · 10 pages, 9 figures
arxiv created 2008/06/20 · openalex publication_date 2008/08/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Some important aspects of the electronic structure of the iron oxypnictides depend very sensitively on small changes in interatomic distances and bond angles within the iron-pnictogen subunit. Using first-principles full-potential electronic structure calculations, we investigate this sensitive dependence, contrasting in particular LaFeAsO and LaFePO. The width of the Fe bands is significantly larger for LaFePO, indicating a better metal and weaker electronic correlations. When calculated at their experimental crystal structures, these two materials have significantly different low-energy band structures. The topology of the Fermi surface changes when going from LaFePO to LaFeAsO, with a three-dimensional hole pocket present in the former case transforming into a tube with two-dimensional dispersion. We show that the low-energy band structure of LaFeAsO evolves toward that of LaFePO as the As atom is lowered closer to the Fe plane with respect to its experimental position. The physical origin of this sensitivity to the iron-pnictogen distance is the covalency of the iron-pnictogen bond, leading to strong hybridization effects. To illustrate this, we construct Wannier functions, which are found to have a large spatial extension when the energy window is restricted to the bands with dominant iron character. Finally, we show that the Fe bandwidth slightly increases as one moves along the rare-earth series in REFeAsO and we discuss the physical origin of this effect.