Renormalization of electron self-energies via their interaction with spin excitations: A first-principles investigation

TL;DR

This paper introduces a first-principles computational approach to analyze inelastic tunneling spectra of magnetic adatoms on surfaces, revealing how spin excitations influence electron self-energies and spectral features.

Contribution

It develops a novel method combining Green function, density functional theory, and many-body perturbation theory to accurately predict inelastic tunneling spectra for magnetic adatoms.

Findings

Spectra are affected by adatom and tip magnetization.

Predicted spectral features are more complex than simple models.

Method successfully characterizes spin-dependent spectral modifications.

Abstract

Access to magnetic excitation spectra of single atoms deposited on surfaces is nowadays possible by means of low-temperature inelastic scanning tunneling spectroscopy. We present a first-principles method for the calculation of inelastic tunneling spectra utilizing the Korringa-Kohn-Rostoker Green function method combined with time-dependent density functional theory and many-body perturbation theory. The key quantity is the electron self-energy describing the coupling of the electrons to the spin excitation within the adsorbate. By investigating Cr, Mn, Fe and Co adatoms on a Cu(111) substrate, we spin-characterize the spectra and demonstrate that their shapes are altered by the magnetization of the adatoms, of the tip and the orbital decay into vacuum. Our method also predicts spectral features more complex than the steps obtained by simpler models for the adsorbate (e.g., localized spin models).