Plasmonic excitations and coupling in atomic wires
Creators: name: Mamiyev, Zamin
Publisher: name: figshare
Year: 2021
Subjects: subject: 20301 Acoustics and Acoustical Devices; Waves
subject: FOS: Physical sciences
subject: FOS: Physical sciences
subject: Applied Physics
subject: Atomic Physics
subject: 20201 Atomic and Molecular Physics
subject: 20299 Atomic, Molecular, Nuclear, Particle and Plasma Physics not elsewhere classified
subject: Computational Physics
subject: 20401 Condensed Matter Characterisation Technique Development
subject: 20402 Condensed Matter Imaging
subject: 20403 Condensed Matter Modelling and Density Functional Theory
subject: Condensed Matter Physics
subject: 20499 Condensed Matter Physics not elsewhere classified
subject: 20404 Electronic and Magnetic Properties of Condensed Matter; Superconductivity
subject: 20601 Degenerate Quantum Gases and Atom Optics
subject: Entropy
subject: 20599 Optical Physics not elsewhere classified
subject: 20504 Photonics, Optoelectronics and Optical Communications
subject: 29999 Physical Sciences not elsewhere classified
subject: Plasma Physics
subject: 20699 Quantum Physics not elsewhere classified
subject: 20406 Surfaces and Structural Properties of Condensed Matter
subject: 30601 Catalysis and Mechanisms of Reactions
subject: FOS: Chemical sciences
subject: FOS: Chemical sciences
subject: 30301 Chemical Characterisation of Materials
subject: 30602 Chemical Thermodynamics and Energetics
subject: 30603 Colloid and Surface Chemistry
subject: Crystallography
subject: Molecular Physics
subject: 30303 Optical Properties of Materials
subject: 30304 Physical Chemistry of Materials
subject: 30699 Physical Chemistry not elsewhere classified
subject: 30206 Solid State Chemistry
subject: 30606 Structural Chemistry and Spectroscopy
subject: 30306 Synthesis of Materials
subject: 30307 Theory and Design of Materials

description: Metal-induced atomic wires on the semiconductor surfaces are the ultimate limit of long-range orderedquasi-one-dimensional electronic systems. In this thesis, the plasmonic excitations and their couplingwith the structural parameters, as well as the role of the embedding medium on the Au atomic wires,self-organized on flat and high-indexed Si surfaces were investigated.The atomic wire systems in the focus of this thesis, Si(111)-(5?2)-Au and Si(hhk)-(1?2)-Au, weregenerated by adsorption of submonolayers of gold onto the reconstructed surfaces. These systems featurea broad range of characteristics that can exemplarily be classified based on the number of atomicchains per terrace, inter-wire spacing, local structure of step edges, number of metallic bands and bandfilling. High-resolution EELS-LEED and SPA-LEED were used as the main experimental methods toaddress the mentioned properties and furthers. These experimental results were compared with theatomistic DFT calculations. Moreover, for the Si(553)-Au system, IR transmittance experiments wereperformed to investigate the optically active standing wave formation after oxidation.As a prominent property of conductive electrons, collective excitation is strongly coupled to the crystallattice, electronic band structure, electronic and spatial confinement as well as properties of thesurrounding physical media. This makes plasmonic excitation an adequate tool to probe a variety ofinteractions and coupling between those parameters associated with metallic structures. Taking thisadvantage, the present thesis investigates plasmonic excitations and their coupling to structural and environmentalparameters. As a result of this investigation, a strong cross-coupling of the electronic andstructural properties was revealed. For example, electronic doping to the Si(553)-Au system enhancesorder along the wires, which also results in band gap opening at the same time. Moreover, modificationof individual structural motifs on the Si(557)-Au surface leads to a unique rearrangement of the bandstructure while preserving the metallicity. Also, combining the plasmon dispersion with calculated bandstructures, the kinetic sequence of the oxidation of the different atomic groups could be studied.For most investigated systems, an almost quantitative agreement between atomistic calculations andplasmon spectroscopy results was achieved, validating the calculated band structure and model used.In particular, the unoccupied part of the band structure was investigated for atomic wire systems. As anexample, for the very first time unoccupied electronic band structure of the Si(111)-(5?2)-Au surfacewas investigated by comparing plasmon dispersion with the available DFT calculated bands. Moreover,doping of the latter surface with surplus Au and atomic H resulted in a metal-insulator transition. However,due to their highly robust anisotropic structure and electronic properties, the doping and oxidationof Si(hhk)-Au systems underline more specific mechanisms in the fine-tuning of metallicity. Some ofthese particular mechanisms include switching of bands, electronic interaction of adjacent terraces,cross-talking of dimerization and band gap opening, self-healing of defects, robust metallicity due tothe site-specific oxidation, and indirect charge transfer to the metallic states, etc. have been extensivelystudied in this thesis.