Density functional theory study of Au-fcc/Ge and Au-hcp/Ge interfaces

In recent years, nanostructures with hexagonal polytypes of gold have been synthesised, opening new possibilities in nanoscience and nanotechnology. As bulk gold crystallizes in the fcc phase, surface effects can play an important role in stabilizing hexagonal gold nanostructures. Here, we investiga...

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Bibliographic Details
Published in:Beilstein journal of nanotechnology 2023, Vol.14 (1), p.1093-1105
Main Authors: Sikora, Olga, Sternik, Małgorzata, Jany, Benedykt R, Krok, Franciszek, Piekarz, Przemysław, Oleś, Andrzej M
Format: Article
Language:English
Subjects:
au/ge heterostructures
Boundary conditions
Crystal defects
Density functional theory
electronic structure
Electrons
Energy
Germanium
Gold
Heterostructures
hexagonal gold
interface energy
Interfaces
Microscopy
Nanoscience
Nanostructure
Nanotechnology
Nanowires
Polytypes
Substrates
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Summary:In recent years, nanostructures with hexagonal polytypes of gold have been synthesised, opening new possibilities in nanoscience and nanotechnology. As bulk gold crystallizes in the fcc phase, surface effects can play an important role in stabilizing hexagonal gold nanostructures. Here, we investigate several heterostructures with Ge substrates, including the fcc and hcp phases of gold that have been observed experimentally. We determine and discuss their interfacial energies and optimized atomic arrangements, comparing the theory results with available experimental data. Our DFT calculations for the Au-fcc(011)/Ge(001) junction show how the presence of defects in the interface layer can help to stabilize the atomic pattern, consistent with microscopic images. Although the Au-hcp/Ge interface is characterized by a similar interface energy, it reveals large atomic displacements due to significant mismatch. Finally, analyzing the electronic properties, we demonstrate that Au/Ge systems have metallic character, but covalent-like bonding states between interfacial Ge and Au atoms are also present.
ISSN:2190-4286
2190-4286
DOI:10.3762/bjnano.14.90