Ab initio study of the TiO$_2$ Rutile(110)/Fe interface

TL;DR

This study uses ab initio density functional theory to analyze the structural, electronic, and magnetic properties of Fe adsorption on TiO2 rutile (110) surfaces, revealing insights into interface bonding, growth modes, and spin polarization.

Contribution

It provides a detailed ab initio analysis of Fe/TiO2 interfaces, explaining experimental structures and magnetic behavior with first-principles calculations.

Findings

Strong interface bonds form with single Fe atoms.

Fe clusters tend to grow in three dimensions due to Fe-Fe bonds.

The interface induces large spin polarization in Fe atoms.

Abstract

Adsorption of Fe on the rutile (110)-surface is investigated by means of {\it ab initio} density functional theory calculations. We discuss the deposition of single Fe atoms, an increasing Fe coverage, as well as the adsorption of small Fe clusters. It is shown that the different interface structures found in experiment can be understood in terms of the adsorption of the Fe atoms landing first on the rutile surface. On the one hand, strong interface bonds form if single Fe atoms are deposited. On the other hand, the Fe-Fe bonds in deposited Fe clusters lead to a three-dimensional growth mode. Mainly ionic Fe-oxide bonds are formed in both cases and the electronic band gap of the surface is reduced due to interface states. Besides the structural and electronic properties, we discuss the influence of the interface on the magnetic properties finding stable Fe moments and induced moments within the interface which leads to a large spin polarization of the Fe atoms at the rutile (110)/Fe interface.