Magnetic nanostructures stabilized by surface-state electrons

Physical Review B - Condensed Matter and Materials Physics

Volumn 70, Issue 7, 2004, Pages

  Stepanyuk, V S ^a   Niebergall, L ^a   Longo, R C ^b   Hergert, W ^c   Bruno, P ^a  

^a MAX PLANCK INSTITUTE OF MICROSTRUCTURE PHYSICS   (Germany)

^b UNIVERSITY OF SANTIAGO DE COMPOSTELA   (Spain)

^c MARTIN LUTHER UNIVERSITY HALLE WITTENBERG   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

COPPER;

AB INITIO CALCULATION; ARTICLE; ATOM; ELECTRON; MAGNETISM; SURFACE PROPERTY;

EID: 19544380026     PISSN: 01631829     EISSN: None     Source Type: Journal    
DOI: 10.1103/PhysRevB.70.075414     Document Type: Article

References (28)

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16. Important details of our studies: We take into account that adatoms couple to 3D bulk bands. The full charge density is used in calculations. The atomic sphere and the full potential approximations give essentially the same results for the substrate-mediated interactions. Calculations beyond the LDA, for example, the GGA (generalized gradient approximation), do not affect the interaction energies at large distances. Relaxations of the atomic position of adatoms are performed by calculating the Hellman-Feynman forces in the full-potential approximation. We have not found any substantial effects of relaxations on the substrate-mediated interactions.
17. e, see also our results in Ref. 11.
18. Due to the exchange splitting of potentials of adatoms a non-monotonic behavior for A and C is found; calculations of the LDOS for all 3d adatoms reveal that for Ti, V, and Cr adatoms the surface-state electrons scatter more strongly at the majority potentials of adatoms, while starting from Mn, the scattering of surface-state electrons by the minority potentials is dominated.
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22. Frustration can arise due to a close competition between different interactions. A simplest example of local geometrical magnetic frustration is the arrangement of three identical spins on an equilateral triangle for the case of the antiferromagnetic pair coupling between atoms, see Ref. 17. The individual interaction energies of all spin pairing in the structure with the hexagonal short-range order cannot be minimized simultaneously if the pair-wise interactions are antiferromagnetic. We note that magnetic coupling in hexagonal nanostructures stabilized by surface-state electrons is mainly determined by the pair-wise exchange interaction.
23. K. A. Fichthorn and M. L. Merrick, Phys. Rev. B 68, 041404 (2003).
24. The existence of free and supported "magic clusters" was discussed; see, for example, S. K. Nayak, P. Jena, V. S. Stepanyuk, W. Hergert, and K. Wildberger, Phys. Rev. B 56, 6952 (1997).
25. N. A. Levanov, V. S. Stepanyuk, and W. Hergert, Phys. Rev. B 61, 2230 (2000); R. C. Longo, V. S. Stepanyuk, W. Hergert, A. Vega, L. J. Gallego, and J. Kirschner, ibid. 69, 073406 (2004).
26. N. A. Levanov, V. S. Stepanyuk, and W. Hergert, Phys. Rev. B 61, 2230 (2000); R. C. Longo, V. S. Stepanyuk, W. Hergert, A. Vega, L. J. Gallego, and J. Kirschner, ibid. 69, 073406 (2004).
27. Binding energies of the hexagonal nanostructures calculated by a pair-wise summation are very close to the ab initio KKR results taking into account many-body interactions, i.e., the using of the pair-wise approximation is well justified.
28. We use ab initio fitted interatomic potentials because fully ab initio calculations of the thermal stability of nanostructures stabilized by surface-state electrons are still out of the possibility of modern computational methods.