# Unoccupied surface and interface states in Pd thin films deposited on Fe/Ir(111) surface

## TL;DR

This study uses first-principles calculations to analyze unoccupied electronic surface and interface states in Pd thin films on Fe/Ir(111), revealing how Pd deposition influences electronic structure relevant for spintronic applications.

## Contribution

It provides a detailed first-principles analysis of surface and interface states in Pd/Fe/Ir(111), highlighting the impact of Pd thickness and Ir spin-orbit coupling on electronic states.

## Key findings

- Emergence of surface and interface states after Pd deposition
- Strong influence of Ir's spin-orbit coupling on electronic states
- Analysis of unoccupied states relevant for spintronic devices

## Abstract

We present a systematic first-principles study of the electronic surface states and resonances occuring in thin films of Pd of various thicknesses deposited on a single ferromagnetic monolayer of Fe on top of Ir(111) substrate. This system is of interest since one Pd layer deposited on Fe/Ir(111) hosts small magnetic skyrmions. The latter are topological magnetic objects with swirling spin-textures with possible implications in the context of spintronic devices since they have the potential to be used as magnetic bits for information technology. The stabilization, detection and manipulation of such non-collinear magnetic entities require a quantitative investigation and a fundamental understanding of their electronic structure. Here we investigate the nature of the unoccupied electronic states in Pd/Fe/Ir(111), which are essential in the large spin-mixing magnetoresistance (XMR) signature captured using non spin-polarized scanning tunnelling microscopy [Crum et al., Nat. Commun. {\bf 6} 8541 (2015); Hanneken et al., Nat. Nanotech. {\bf 10}, 1039 (2015)]. To provide a complete analysis, we investigate bare Fe/Ir(111) and Pd$_{n=2,7}$/Fe/Ir(111) surfaces. Our results demonstrate the emergence of surface and interface states after deposition of Pd monolayers, which are strongly impacted by the large spin-orbit coupling of Ir surface.