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Nanospace charge polarization of monatomic‐layered platinum cluster disk constructed on silicon(111)‐7 × 7 surface
Author(s) -
Yasumatsu Hisato,
Murugan Palanichamy,
Kawazoe Yoshiyuki
Publication year - 2012
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201100563
Subject(s) - cluster (spacecraft) , monatomic ion , platinum , electron , silicon , valence electron , chemistry , materials science , atomic physics , crystallography , molecular physics , physics , biochemistry , organic chemistry , quantum mechanics , computer science , programming language , catalysis
We studied geometric and electronic structures of a platinum cluster disk consisting 30 Pt atoms on the Si(111)‐7 × 7 surface by STM experiments (see left panel) and first principles calculations. It was found that the high stability of the cluster disk on the Si surface originates from the platinum–silicide bonds as strong as ∼45 eV per cluster, which are formed by electron transfer from the 5d orbital of the Pt atoms to the 3s and 3p ones of the Si atoms. This finding gives an essential interpretation to the experimental discovery that valence electrons in an occupied molecular orbital of the Pt 30 /Si system are distributed in a wider region than the locations of the Pt atoms. It appeared that electron accumulation at the interface between the cluster and the substrate induces two‐dimensional charge polarization in a nanospace as shown in right panel due to a combination of a metallic nature of the cluster disk and a highly resistive nature of the Si surface.STM image (left) of a monatomic‐layered platinum cluster disk, Pt 30 , constructed on the Si(111) surface. Schematic image (right) of two‐dimensional charge polarization; the Pt‐5d electrons are distributed out of the cluster, so that the centre and the periphery of the cluster are charged positively and negatively, respectively.