Dynamic lattice distortion in metallic nanocrystals. (15th January 2023)

• Record Type: Journal Article
• Authors: Leonardi, Alberto; Leoni, Matteo
• Is Part Of: Acta materialia. Volume 243(2023)
• Publication Date: 2023-01-15
• Subjects: Metallic nanocrystals -- Dynamic lattice distortion -- Structure anisotropy -- Debye-Waller factor -- Total scattering; AC average configuration (of atomistic model) -- ALDi anisotropic lattice distortion (model) -- BuILD bulk isotropic lattice distortion (approximation) -- CD correlated Debye (model) -- CE correlated Einstein (model) -- CVF common volume function -- DC dynamic configuration (of atomistic model) -- D-PDF directional-pair distribution function -- DSE Debye scattering equation -- DWF Debye-Waller factor -- EAM embedded atom method -- EC equilibrium configuration (of atomistic model) -- FCC face-centred cubic (structure) -- IC ideal configuration (of atomistic model) -- IRMSD∥ independent relative mean square displacement (of neighbour atoms) parallel to the atom-pair direction -- MD molecular dynamics -- MSD (atom) mean square displacement -- MSRD∥ mean square relative displacement (of neighbor atoms) parallel to the atom-pair direction -- MSRD⊥ mean square relative displacement (of neighbor atoms) orthogonal to the atom-pair direction -- NC nanocrystal -- NPT constant number, pressure, and temperature (ensemble) -- NVE constant number, volume, and energy (ensemble) -- NVT constant number, volume, and temperature (ensemble) -- PDF pair distribution function -- PXRD powder X-ray diffraction -- RDF radial distribution function -- VDOS vibrational density of states -- WPDFM whole pair distribution function modeling -- XAFS X-ray absorption fine structure; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2022.118491
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Advanced design of metallic nanocrystals (NCs) for plasmonic applications requires control of the dynamic lattice distortion. Here we apply atomistic simulations coupled with total scattering to study the lattice vibrations induced by the thermal motion of atoms in Pd NCs. Quantitative analysis of the dynamic-relative displacement of neighbor atoms details the correlation of the lattice vibrations fading with the increase of atom-pair distance. Negative correlations are revealed from displacements of far-neighbor atoms with pair direction normal to the crystal surface, which we explain as breathing vibration modes. We propose a phenomenological dynamical model to predict the influence of material structure and NCs shape on the dynamic lattice distortion. Lattice vibrations show a marked dependence on the atom-pair direction, which enhances with decreasing size and cubic shape of crystals. Our work demonstrates that, if proper distortion models are used, the thermal motion of atoms near the surface of metallic NCs can be observed from total scattering data. Further simulations and experiments will support the future extension to compositionally and architecturally complex nanoparticles of the anisotropic lattice distortion model (ALDi) that is here introduced. Graphical abstract: Image, graphical abstract