Electronic structure of LaFe1-xCoxAsO from first principle calculations

TL;DR

This study uses first-principles calculations to analyze the electronic structure and bonding in LaFe1-xCoxAsO, revealing how Co doping influences the Fermi level and suppresses SDW transition.

Contribution

It provides detailed insights into the bonding and electronic changes due to Co doping in LaFe1-xCoxAsO using first-principles methods.

Findings

La-O and TM-As bonds are strongly covalent.

LaO and TMAs layers interact ionically.

Co doping modifies the Fermi level, suppressing SDW transition.

Abstract

Based on the first-principles calculations, we have investigated the geometry, binding properties, density of states and band structures of the novel superconductor LaFe1-xCoxAsO and its parent compounds with the ZrCuSiAs structure. We demonstrate that La-O bond and TM-As (TM=Fe or Co) bond are both strongly covalent, while the LaO and TMAs layers have an almost ionic interaction through the Bader charge analysis. Partial substitution of iron with cobalt modify the Fermi level from a steep edge to a flat slope, which explains why in this system Co doping suppresses the spin density wave (SDW) transition.