Theory of quasiparticle spectra for Fe, Co, and Ni: bulk and surface

TL;DR

This paper investigates the correlated electronic structures of Fe, Co, and Ni using LDA+DMFT, revealing strong correlation effects, surface dependencies, and the influence of dimensionality on quasiparticle spectra.

Contribution

It provides a detailed analysis of quasiparticle spectra and surface effects in Fe, Co, and Ni using a novel full-potential LDA+DMFT approach, highlighting surface and dimensionality influences.

Findings

Strong correlation effects in majority spin electrons.

Surface self-energy depends on the number of nearest neighbors.

Correlation effects diminish rapidly within two layers from the surface.

Abstract

The correlated electronic structure of iron, cobalt and nickel is investigated within the dynamical mean-field theory formalism, using the newly developed full-potential LMTO-based LDA+DMFT code. Detailed analysis of the calculated electron self-energy, density of states and the spectral density are presented for these metals. It has been found that all these elements show strong correlation effects for majority spin electrons, such as strong damping of quasiparticles and formation of a density of states satellite at about -7 eV below the Fermi level. The LDA+DMFT data for fcc nickel and cobalt (111) surfaces and bcc iron (001) surface is also presented. The electron self energy is found to depend strongly on the number of nearest neighbors, and it practically reaches the bulk value already in the second layer from the surface. The dependence of correlation effects on the dimensionality of the problem is also discussed.