Pseudogap Value in the Energy Spectrum of LaOFeAs: Fixed Spin Moment Treatment

TL;DR

This paper investigates the pseudogap formation in LaOFeAs during the spin density wave transition, highlighting the limitations of standard density functional theory and the improved accuracy achieved with fixed spin moment methods.

Contribution

It demonstrates that using fixed spin moment treatment aligns theoretical predictions more closely with experimental data for LaOFeAs.

Findings

Pseudogap formation observed during spin density wave transition.

Fixed spin moment approach improves theoretical-experimental agreement.

Standard density functional theory underestimates pseudogap and density of states changes.

Abstract

The experimental data available up to date in literature corresponding to the paramagnetic - spin density wave transition in nonsuperconducting LaOFeAs are discussed. In particular, we pay attention that upon spin density wave transition there is a relative decrease of the density of states on the Fermi level and a pseudogap formation. The values of these quantities are not properly described in frames of the density functional theory. The agreement of them with experimental estimations becomes more accurate with the use of fixed spin moment procedure when iron spin moment is set to experimental value. Strong electron correlations which are not included into the present calculation scheme may lead both to the decrease of spin moment and renormalization of energy spectrum in the vicinity of the Fermi level for correct description of discussed characteristics.