Fe Nanoclusters on the Ge(001) Surface Studied by Scanning Tunneling Microscopy, Density Functional Theory Calculations and X-Ray Magnetic Circular Dichroism

TL;DR

This study combines STM, DFT, and XMCD to investigate the growth, structure, and magnetic properties of Fe nanoclusters on Ge(001), revealing their formation, size, and superparamagnetic behavior.

Contribution

It provides a detailed analysis of Fe nanocluster formation and magnetic properties on Ge(001) using combined experimental and theoretical methods, highlighting temperature effects.

Findings

Fe nanoclusters are well-ordered and uniform in size.

Two types of nanoclusters with 4 or 16 Fe atoms were observed.

Nanoclusters exhibit superparamagnetic behavior.

Abstract

The growth of Fe nanoclusters on the Ge(001) surface has been studied using lowtemperature scanning tunnelling microscopy (STM) and density functional theory (DFT) calculations. STM results indicate that Fe nucleates on the Ge(001) surface, forming wellordered nanoclusters of uniform size. Depending on the preparation conditions, two types of nanoclusters were observed having either four or sixteen Fe atoms within a nanocluster. The results were confirmed by DFT calculations. Annealing the nanoclusters at 420 K leads to the formation of nanorow structures, due to cluster mobility at such temperature. The Fe nanoclusters and nanorow structures formed on the Ge(001) surface show a superparamagnetic behaviour as measured by X-ray magnetic circular dichroism.