Surface segregation energy in bcc Fe-rich Fe-Cr alloys

The exact muffin-tin orbitals (EMTO) technique in conjunction with the coherent-potential approximation (CPA) as well as the projector-augmented-wave (PAW) method have been used to calculate the surface segregation energy of Cr at the (100) surface of Fe-rich bcc Fe-Cr alloys. We find that PAW resul...

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2007-06, Vol.75 (24), p.245406, Article 245406
Main Authors: Ponomareva, A. V., Isaev, E. I., Skorodumova, N. V., Vekilov, Yu. Kh, Abrikosov, I. A.
Format: Article
Language:English
Subjects:
BCC LATTICES
CHROMIUM ALLOYS
FERROMAGNETIC MATERIALS
Fysik
GREEN FUNCTION
INTERACTIONS
IRON ALLOYS
MATERIALS SCIENCE
MUFFIN-TIN POTENTIAL
NATURAL SCIENCES
NATURVETENSKAP
Physics
SEGREGATION
SIMULATION
SURFACES
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Summary:The exact muffin-tin orbitals (EMTO) technique in conjunction with the coherent-potential approximation (CPA) as well as the projector-augmented-wave (PAW) method have been used to calculate the surface segregation energy of Cr at the (100) surface of Fe-rich bcc Fe-Cr alloys. We find that PAW results strongly depend on the supercell size used in the calculations. In particular, for large supercells, the surface segregation energy of Cr is positive, which means that Cr should not segregate toward the surface of diluted alloys. This is in agreement with our EMTO-CPA results as well as previous surface Green's-function calculations. However, the surface segregation energy of Cr is negative if small unit cells are used for simulations. This is in agreement with previous full-potential supercell calculations. We explain such a size dependence by a peculiar concentration dependence of interatomic interactions in ferromagnetic Fe-Cr alloys.
ISSN:1098-0121
1550-235X
1550-235X
DOI:10.1103/PhysRevB.75.245406