Quasiperiodic gallium adlayer on i-Al-Pd-Mn

Fuente: arXiv
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Auteurs principaux: Bhakuni, Pramod, Krajčí, Marian, Barman, Sudipta Roy
Format: Preprint
Publié: 2023
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author Bhakuni, Pramod
Krajčí, Marian
Barman, Sudipta Roy
author_facet Bhakuni, Pramod
Krajčí, Marian
Barman, Sudipta Roy
contents Using scanning tunneling microscopy (STM), low energy electron diffraction (LEED), and density functional theory (DFT), we demonstrate the formation of quasicrystalline gallium adlayer on icosahedral ($i$)-Al-Pd-Mn. Quasiperiodic motifs are evident in the STM topography images, including the Ga white flower (GaWF) and $τ$ inflated GaWF ($τ$-GaWF), where $τ$ is the golden mean. A larger and more complicated ring motif is also identified, comprised of a bright center and an outer ring of pentagons. The fast Fourier transform of the STM images exhibits distinct quasiperiodic spots, thereby establishing quasiperiodicity on a length scale of $\sim$350 nm. Based on our DFT calculations, the preferred adsorption sites of Ga on i-Al-Pd-Mn are determined to be either the Mn atoms at the center of the Penrose P1 tile or the vertices of the P1 tile containing Pd atoms at the center of a cluster of 5 Al atoms (5-Al). The GaWF motif is modeled by an inner 6 atom Ga cluster (6-Ga) around the central Mn atom and an outer ring of 5 Ga atoms adsorbed at the centers of the 5-Al clusters, both having pentagonal symmetry. The $τ$-GaWF motif is modeled by the 6-Ga arranged on the $τ$-P1 tiling, while the ring motif is modeled by Ga atoms adsorbed at the center of 5-Al clusters above a Pd atom. The side lengths and diameters of the GaWF, $τ$-GaWF, and the ring motifs are $τ$ scaled and show excellent agreement with the DFT-based models. An additional indication of the quasiperiodic characteristics of the Ga monolayer is the 5-fold LEED patterns that were detected throughout the entire range of beam energy that was measured.
format Preprint
id arxiv_https___arxiv_org_abs_2312_12005
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Quasiperiodic gallium adlayer on i-Al-Pd-Mn
Bhakuni, Pramod
Krajčí, Marian
Barman, Sudipta Roy
Materials Science
Using scanning tunneling microscopy (STM), low energy electron diffraction (LEED), and density functional theory (DFT), we demonstrate the formation of quasicrystalline gallium adlayer on icosahedral ($i$)-Al-Pd-Mn. Quasiperiodic motifs are evident in the STM topography images, including the Ga white flower (GaWF) and $τ$ inflated GaWF ($τ$-GaWF), where $τ$ is the golden mean. A larger and more complicated ring motif is also identified, comprised of a bright center and an outer ring of pentagons. The fast Fourier transform of the STM images exhibits distinct quasiperiodic spots, thereby establishing quasiperiodicity on a length scale of $\sim$350 nm. Based on our DFT calculations, the preferred adsorption sites of Ga on i-Al-Pd-Mn are determined to be either the Mn atoms at the center of the Penrose P1 tile or the vertices of the P1 tile containing Pd atoms at the center of a cluster of 5 Al atoms (5-Al). The GaWF motif is modeled by an inner 6 atom Ga cluster (6-Ga) around the central Mn atom and an outer ring of 5 Ga atoms adsorbed at the centers of the 5-Al clusters, both having pentagonal symmetry. The $τ$-GaWF motif is modeled by the 6-Ga arranged on the $τ$-P1 tiling, while the ring motif is modeled by Ga atoms adsorbed at the center of 5-Al clusters above a Pd atom. The side lengths and diameters of the GaWF, $τ$-GaWF, and the ring motifs are $τ$ scaled and show excellent agreement with the DFT-based models. An additional indication of the quasiperiodic characteristics of the Ga monolayer is the 5-fold LEED patterns that were detected throughout the entire range of beam energy that was measured.
title Quasiperiodic gallium adlayer on i-Al-Pd-Mn
topic Materials Science
url https://arxiv.org/abs/2312.12005