Sökning: onr:"swepub:oai:DiVA.org:lnu-69012" >
Theoretical modelin...
Theoretical modeling of scanning tunneling microscopy
-
- Gustafsson, Alexander, 1982- (författare)
- Linnéuniversitetet,Institutionen för fysik och elektroteknik (IFE),Condensed Matter Physics
-
Paulsson, Magnus (preses)
-
- Iribas Cerdá, Jorge, Dr. (opponent)
- Materials Science Institute of Matdrid, Spanish National Research Council
-
(creator_code:org_t)
- ISBN 9789188357960
- Växjö : Linnaeus University Press, 2017
- Engelska 133 s.
-
Serie: Linnaeus University Dissertations ; 300
- Relaterad länk:
-
https://lnu.diva-por... (primary) (Raw object)
-
visa fler...
-
https://lnu.diva-por... (Preview)
-
https://urn.kb.se/re...
-
visa färre...
Abstract
Ämnesord
Stäng
- 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. A finite difference approximation is used to define the vacuum Hamiltonian, from which accurate vacuum wave functions are calculated using equations based on standard single-particle Green’s function techniques, and ultimately used to compute the conductance. By averaging over the lateral reciprocal space, the theory is compared to a series of high-quality experiments in the low- bias limit, concerning copper surfaces with adsorbed carbon monoxide (CO) species and adsorbate atoms, scanned by pure and CO-functionalized copper tips. The theory compares well to the experiments, and allows for further insights into the elastic tunneling regime.A second significant project in this thesis concerns first-principles calculations of a simple chemical reaction of a hydroxyl (oxygen-deuterium) monomer adsorbed on a copper surface. The reaction mechanism is provided by tunneling electrons that, via a finite electron-vibration coupling, trigger the deuterium atom to flip between two nearly identical configurational states along a frustrated rotational motion. The theory suggests that the reaction primarily occurs via nuclear tunneling for the deuterium atom through the estimated reaction barrier, and that over-barrier ladder climbing processes are unlikely.
Ämnesord
- NATURVETENSKAP -- Fysik -- Den kondenserade materiens fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Condensed Matter Physics (hsv//eng)
Nyckelord
- Scanning tunneling microscopy
- Computational models
- Quantum tunneling
- Green's functions
- Density functional theory
- Condensed Matter Physics
- Kondenserade materians fysik
Publikations- och innehållstyp
- vet (ämneskategori)
- dok (ämneskategori)
Hitta via bibliotek
Till lärosätets databas