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DFT characterization of nanostructured germanium surfaces induced by cobalt atoms
Author(s) -
Stephan Régis,
Hanf MarieChristine,
Wetzel Patrick,
Dulot Frédéric,
Sonnet Philippe
Publication year - 2014
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.5354
Subject(s) - germanium , scanning tunneling microscope , density functional theory , cobalt , crystallography , chemistry , characterization (materials science) , surface (topology) , atom (system on chip) , materials science , molecular physics , chemical physics , silicon , nanotechnology , computational chemistry , geometry , inorganic chemistry , mathematics , organic chemistry , computer science , embedded system
By deposition in ultra‐high vacuum of cobalt on a Ge(111)– c (2 × 8) surface, Mocking et al . obtained a13 × 13 − R 13.9 ° surface reconstruction. In the present paper, we analyse the related atomic structure, proposed by these authors, by means of density functional theory calculations. The surface presents ordered clusters that consist of six Ge atoms arranged in a triangle, lying above three Co atoms. The latter are located at substitutional positions within the top plane of the Ge(111) first bilayer. These clusters are similar to what is obtained on part of the Co‐induced Si(111)13 × 13 − R 13.9 ° surface. For this surface, the clusters are terminated either by six Si atoms or by one, two or three adatoms above the six Si atoms. As the Co–Ge clusters systematically display six protrusions in the scanning tunnelling microscopy measurements by Mocking et al ., we investigated why Ge adatoms are not present. Comparison of the Gibbs energy, interatomic distances, as well as charge density indicates that Ge adatoms on top of Co‐Ge clusters are less stable than Si adatoms in the Co‐Si system. Copyright © 2013 John Wiley & Sons, Ltd.