Structural Stability of Si(001) and Ge(001) in External Electric Fields

The effects of external electrostatic fields normal to surfaces, E ext , on the structural stability of Si(001) and Ge(001) have been investigated using first-principles total energy calculations. It has been shown that the c(4×2) surface is more stable than the p(2×2) surface for both Si(001) and G...

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Bibliographic Details
Published inJapanese Journal of Applied Physics Vol. 44; no. 7S; p. 5413
Main Authors Nakamura, Jun, Natori, Akiko
Format Journal Article
LanguageEnglish
Published 01.07.2005
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Summary:The effects of external electrostatic fields normal to surfaces, E ext , on the structural stability of Si(001) and Ge(001) have been investigated using first-principles total energy calculations. It has been shown that the c(4×2) surface is more stable than the p(2×2) surface for both Si(001) and Ge(001) even with a finite electric field whose strength is typical of STM experiments. On the other hand, it has been revealed that the energy barrier for dimer flipping, E B , shows different dependences between the Si(001)- and Ge(001)-(2×1) surfaces: E B at Si(001) changes in proportion to E ext , but hardly does at Ge(001). Such a difference is explained by the difference in the rehybridization of buckled dimers between the reconstructed surfaces of Si(001) and Ge(001), which originates from the difference in the s-p separation of valence orbitals between Si and Ge.
ISSN:0021-4922
1347-4065
DOI:10.1143/JJAP.44.5413