Speaker
Description
Accessing the interfacial electronic structure of ferromagnets (FM) with spin and momentum resolution is crucial for predicting the electronic functionality of hybrid interfaces. In particular, the adsorption of non-magnetic atoms or molecules on a ferromagnetic transition-metal surface creates complex hybrid systems exhibiting a variety of different physical phenomena.
First, I will describe how oxygen adsorption strongly modifies the electronic properties of the pristine Fe(100) surface (O–Fe), enhancing electronic correlations [1]. The spin-dependent electronic structure is accessed by spin-resolved photoemission electron microscopy, combined with advanced theoretical approaches that explicitly account for electron correlation effects.
This oxygen-passivated surface provides a versatile platform for molecular adsorption. In particular, we investigate pentacene adsorption on O–Fe(100), where the enhanced electron correlation at the surface promotes strong molecule–metal interaction. A combination of photoemission orbital tomography (POT), scanning tunneling spectroscopy (STS), and electronic structure calculations reveals pronounced hybridization between the pentacene frontier orbitals and the Fe 3d states. A tailored DFT+U approach with a negative effective on-site interaction (Ueff = −3.1 eV) reproduces the experimentally observed reduction in d-band spin splitting and band narrowing, consistent with dynamical mean-field theory. These correlation-induced modifications enhance the energetic overlap between metal d-states and molecular orbitals, driving a transition from physisorption to strong chemisorption [2].
[1] D. M. Janas et. al. Advanced Materials 2023, 35, 2205698.
[2] D. M. Janas et. al. Small 2025, 22, e08952