Growth modes of Fe(110) revisited: a contribution of self-assembly to magnetic materials

TL;DR

This study revisits Fe(110) epitaxial growth on W(110) and Mo(110), revealing a bimodal island distribution and demonstrating self-assembly techniques for nanostructure fabrication, with implications for magnetic materials.

Contribution

It provides new insights into the growth modes of Fe on W(110) and Mo(110), highlighting the role of self-assembly in forming nanostructures and clarifying the factors influencing island height.

Findings

Bimodal island distribution in Fe growth on W(110) and Mo(110)

Self-organized nanostructure arrays achieved via step decoration

Preferred island heights are influenced by interfacial energy and lattice parameters

Abstract

We have revisited the epitaxial growth modes of Fe on W(110) and Mo(110), and propose an overview or our contribution to the field. We show that the Stranski-Krastanov growth mode, recognized for a long time in these systems, is in fact characterized by a bimodal distribution of islands for growth temperature in the range 250-700°C. We observe firstly compact islands whose shape is determined by Wulff-Kaischev's theorem, secondly thin and flat islands that display a preferred height, ie independant from nominal thickness and deposition procedure (1.4nm for Mo, and 5.5nm for W on the average). We used this effect to fabricate self-organized arrays of nanometers-thick stripes by step decoration. Self-assembled nano-ties are also obtained for nucleation of the flat islands on Mo at fairly high temperature, ie 800°C. Finally, using interfacial layers and solid solutions we separate two effects on the preferred height, first that of the interfacial energy, second that of the continuously-varying lattice parameter of the growth surface.