Many-body effects on Cr(001) surfaces: An LDA+DMFT study

TL;DR

This study combines ab initio calculations with dynamical mean-field theory to investigate the electronic structure of Cr(001) surfaces, revealing the importance of dynamic electron correlations in forming a low-energy resonance.

Contribution

It provides a detailed orbitally resolved spectral function of Cr(001) surfaces, clarifying the origin of the resonance through many-body effects, and reconciles conflicting experimental observations.

Findings

Dynamic electron correlations create a low-energy resonance in specific orbitals.

The spectral function matches experimental photoemission data.

The study clarifies the origin of the Cr(001) surface resonance.

Abstract

The electronic structure of the Cr(001) surface with its sharp resonance at the Fermi level is a subject of controversial debate of many experimental and theoretical works. To date, it is unclear whether the origin of this resonance is an orbital Kondo or an electron-phonon coupling effect. We have combined ab initio density functional calculations with dynamical mean-field simulations to calculate the orbitally resolved spectral function of the Cr(001) surface. The calculated orbital character and shape of the spectrum is in agreement with data from (inverse) photoemission experiments. We find that dynamic electron correlations crucially influence the surface electronic structure and lead to a low energy resonance in the $d_{z^2}$ and $d_{xz/yz}$ orbitals. Our results help to reconvene controversial experimental results from (I)PES and STM measurements.