Magnetische Adatome und Nanostrukturen auf Metalloberflächen
Magnetische Adatome und Nanostrukturen auf Metalloberflächen
We present ab-initio electronic structure calculations of the electronic propertiesof impurities on metallic surfaces in the framework of the local density approximationbased on the Greens function approach proposed by Korringa, Kohn and Rostoker(KKR). Motivated by the results of scanning tunneling...
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Personal Name(s): | Nonas, Bereshad Rene (Corresponding author) |
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Contributing Institute: |
Publikationen vor 2000; PRE-2000; Retrocat |
Imprint: |
Jülich
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2000
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Physical Description: |
IV, 140 p. |
Document Type: |
Report Book |
Research Program: |
Addenda |
Series Title: |
Berichte des Forschungszentrums Jülich
3791 |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
We present ab-initio electronic structure calculations of the electronic propertiesof impurities on metallic surfaces in the framework of the local density approximationbased on the Greens function approach proposed by Korringa, Kohn and Rostoker(KKR). Motivated by the results of scanning tunneling microscope experiments(STM) of Cr-atoms on the (001) surface of Iron, we study in the first part of thisreport the properties of $\textit{3d}$-impurities on the Fe(001) surface. Our total energycalculations predict interdiffusion of nearly all impurities into the first surface layerby an atomic exchange process between the impurity atom and one of the substrateatoms in the surface layer. Furthermore our results show a strong repulsion of dimersconsisting of elements at the beginning of the $\textit{3d}$-transition series. Both results arein good agreement with the STM experiments for the Cr/Fe system. A comparisonof the calculated densities of state in the vacuum region with the STM results shows,that a realistic calenlotion of the tunneling current has to take into account the fullnonspherical contributions of the vacuum potential.In the second part we present a full relativistic extension of the KKR formalismfor surface calculations. After testing the validity of the method by means of consistencycalculations and comparison to other results we show results for single $\textit{3d}$-,$\textit{4d}$- and $\textit{5d}$-transition metal impurities on the (001) surfaces of Silver and Gold . Thespin-orbit interaction leads on the one hand to reduced spin moments but induces onthe other hand strong orbital moments, which rise under the additional influence ofthe orbital polarization term suggested by Brooks to the saure order of magnitude asthe local spin moments (e.g. Os on Ag: spin moment 2.0$\mu_{B}$; orbital moment 1.8$\mu_{B}$).We also present results for the large magnetocrystalline anisotropy energies of thesesystems (e.g. 20meV for Re on Ag), calculated by an extension of Lloyds formula tocomplex energies. |