Work

Thermomigration of Au-Ge microdroplets on Ge(111): Atomic mechanisms and effects on surface morphology

Year: 2025

Type: article

Abstract: The motion of microdroplets under thermal gradients, also known as thermomigration (TM), plays a critical role in a wide range of surface phenomena and technological applications. In this work, we study the TM behavior of Au-Ge micro-droplets on Ge(111) surfaces and show that the droplet motion leads to the formation of atomically flat terraces, which are essential for thin film epitaxy. Experimental observations are combined with a microscopic model to investigate droplet motion and the formation of flat atomic terraces. Our results show that, at low temperatures, droplet velocity increases with size, but this size dependence diminishes as the temperature rises. The microscopic model we develop is based on thermally activated detachment, diffusion, and attachment of solute (Ge) atoms across the droplet, driven by a temperature-dependent concentration difference between the leading edge and the trailing edge. The model reproduces the experimental trends. Our results provide insights into the fundamental mechanisms of droplet TM and suggest ways to control surface morphology.

Source: Physical Review Materials

DOI: 10.1103/p1lf-r9y9

Authors: Nayef Abu Dahech, Frédéric Leroy, Pierre Müller, Fabien Cheynis, Stefano Curiotto

Institutions: Centre National de la Recherche Scientifique, Aix-Marseille Université, Centre Interdisciplinaire de Nanoscience de Marseille

Language: English

Topic: Fluid Dynamics and Thin Films

Subfield: Computational Mechanics

Field: Engineering

Domain: Physical Sciences

Open Access status: green

Funder: Agence Nationale de la Recherche

Awards: G5256542555, Manipulating surfaces by thermomigration: towards thermal tweezers