Sökning: "Scanning Tunneling Microscopy STM"

Visar resultat 1 - 5 av 43 avhandlingar innehållade orden Scanning Tunneling Microscopy STM.

1. 1. Theoretical modeling of scanning tunneling microscopy

   Författare :Alexander Gustafsson; Magnus Paulsson; Jorge Iribas Cerdá; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Scanning tunneling microscopy; Computational models; Quantum tunneling; Green s functions; Density functional theory; Condensed Matter Physics; Kondenserade materians fysik;

   Sammanfattning : The main body of this thesis describes how to calculate scanning tunneling microscopy (STM) images from first-principles methods. The theory is based on localized orbital density functional theory (DFT), whose limitations for large-vacuum STM models are resolved by propagating localized-basis wave functions close to the surface into the vacuum region in real space. LÄS MER

3. 2. Scanning Tunneling Microscopy Induced Luminescence Studies of Semiconductor Nanostructures

   Författare :Ulf Håkanson; Fasta tillståndets fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; transmission electron microscopy TEM ; III-V semiconductors; low-dimensional structures; nanostructures; single dot spectroscopy; Stranski-Krastanow; quantum dot QD ; Semiconductory physics; polarization; ordering; InP; GaInP; photon mapping; scanning tunneling microscopy STM ; scanning tunneling luminescence STL ; Halvledarfysik; Fysicumarkivet A:2003:Håkanson;

   Sammanfattning : This thesis treats scanning tunneling luminescence (STL) investigations of semiconductor nanostructures. The STL technique combines scanning tunneling microscopy (STM) with detection of photons, induced by the tunneling electrons. The high spatial resolution in STM and the local excitation allow for optical investigations on the nanometer-scale. LÄS MER

4. 3. Electronic and Geometrical Structure of Phthalocyanines on Surfaces : An Electron Spectroscopy and Scanning Tunneling Microscopy Study

   Författare :John Åhlund; Carla Puglia; Joachim Schiessling; Emanuelle Göthelid; Nils Mårtensson; Nadine Witkowski; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; PhotoElectron Spectroscopy PES ; X-ray Absorption Spectroscopy XAS ; UltraViolet-Visible absorption spectroscopy UV-Vis ; Scanning Tunneling Microscopy STM ; Phthalocyanine Pc ; Iron Phthalocyanine FePc ; metal-free Phthalocyanine H2Pc ; Zinc Phthalocyanine ZnPc ; Graphite HOPG ; Indium Antimony InSb ; Surface science; Fysik;

   Sammanfattning : Core- and Valence Photoelectron Spectroscopy (PES), X-ray- and Ultraviolet-Visible Absorption Spectroscopy (XAS and UV-Vis), Scanning Tunneling Microscopy (STM) and Density Functional Theory (DFT) calculations are used to study the electronic and geometrical structure of a class of macro-cyclic molecules, Phthalocyanines (Pc), on surfaces. These molecules are widely studied due to their application in many different fields. LÄS MER

5. 4. Modeling of non-equilibrium scanning probe microscopy

   Författare :Alexander Gustafsson; Magnus Paulsson; Tchavdar Todorov; Linnéuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; scanning tunneling microscopy; molecular dynamics; density functional theory; non-equilibrium Green s functions; Condensed Matter Physics; Kondenserade materians fysik;

   Sammanfattning : The work in this thesis is basically divided into two related but separate investigations.The first part treats simple chemical reactions of adsorbate molecules on metallic surfaces, induced by means of a scanning tunneling probe (STM). The investigation serves as a parameter free extension to existing theories. LÄS MER

7. 5. On the Properties of Some Strongly Correlated Systems - Analytical and Numerical Studies

   Författare :Jurij Smakov; KTH; []
   Nyckelord :mean field theory; magnetic multilayers; Curie temperature; compensation temperature; scanning tunneling microscopy; tunneling; superconductivity; local density of states; Josephson effect; tunneling Hamiltonian formalism; impurities in superconducto;

   Sammanfattning : This thesis is dedicated to analytical and numerical studiesof a few models of strongly correlated systems and thedevelopment of techniques for such studies. The common name"strongly correlated" refers to systems in which theinteractions (correlations) between the constituent particleslead to nontrivial properties, such as various types ofmagnetism, superconductivity, and exotic phases. LÄS MER