Diffusion and Nucleation Phenomena on Metal Surfaces

Diffusion and nucleation on metal surfaces govern a spectrum of processes from thin-film growth to nanoparticle formation and catalysis. Surface diffusion involves the thermally activated migration of adatoms, clusters or vacancies across crystallographic terraces, steps and defects. Nucleation marks the onset of stable island formation, determined by the interplay between surface energy, strain and kinetic barriers. At reduced dimensions, metal surfaces often reconstruct to minimise free energy, giving rise to quasi-hexagonal, c(2×2) or other periodic motifs that modify local diffusion pathways. Modern experiments combine scanning tunnelling microscopy with in situ thermal control to resolve atomistic motion, while theory employs density functional calculations and lattice kinetic Monte Carlo simulations to quantify energy barriers and prefactors. Together these approaches have revealed late transition states on Au(111), the role of alloying in mixed-metal systems and the influence of step density on critical nucleus size. Insights into diffusion-mediated surface restructuring underpin advances in heterogeneous catalysis, corrosion resistance, device fabrication and the design of self-assembled nanostructures.

Research from Nature Portfolio

Recent studies have deployed lattice kinetic Monte Carlo methods to elucidate atomic diffusion on Au(111) films. By introducing coordination-averaged energies consistent with bulk gold phases, simulations reproduce an activation barrier of approximately 0.2 eV and diffusion prefactors in the range of 40–50 Å2 ps–1. These results shed light on the temperature-driven transition from smooth surface transport to faceting and agree closely with experimental melting observations in 2–8 nm gold nanoparticles.

Investigations of platinum deposition on the quasi-hexagonal Au(100) template have provided a detailed picture of nucleation and alloy formation. Scanning tunnelling microscopy reveals that sub-monolayer Pt coverage induces elongated monolayer islands of disordered Pt–Au alloy coexisting with quantised nanowire features. Controlled annealing between 100 °C and 150 °C transforms these islands into a flat Pt–Au alloy interspersed with hex-stripe domains and c(2×2) ordered patches. Ab initio calculations confirm a redistribution of d-state electrons and the formation of Pt–Au bonding, offering a mechanistic basis for the enhanced catalytic activity of bimetallic surfaces.

Diffusion and Nucleation Phenomena on Metal Surfaces publication trend

The graph below shows the total number of articles in diffusion and nucleation phenomena on metal surfaces across all publications each year (not limited to Nature Index journals).

Technical terms

Adatom: An atom adsorbed onto a surface, capable of migrating under thermal activation.

Activation barrier: The energy required for an atom or cluster to move from one site to another on a surface.

Surface reconstruction: A rearrangement of surface atoms into a new periodic structure that lowers surface energy.

Lattice kinetic Monte Carlo: A simulation technique that models diffusion dynamics by sampling possible moves on a discrete lattice using energy barriers.

Scanning tunnelling microscopy (STM): An imaging method that maps surface topography and electronic states with atomic resolution by measuring tunnelling current.

Density functional theory (DFT): A quantum mechanical modelling approach to calculate electronic structure and energetics of atoms on surfaces.

References

1. The Lattice Kinetic Monte Carlo Simulation of Atomic Diffusion and Structural Transition for Gold. Scientific Reports (2016).
2. Large-scale surface reconstruction energetics of Pt(100) and Au(100) by all-electron density functional theory. Physical Review B (2010).
3. Simulation of reduction of oxidized metal nanoparticles. Reaction Kinetics, Mechanisms and Catalysis (2023).
4. Structural and electronic properties of Pt modified Au(100) surface. Scientific Reports (2022).
5. LEED-IV analyses of tellurium adsorbate structures on iridium and gold surfaces. Surface Science (2024).