Energetics and bias-dependent scanning tunneling microscopy images of Si ad-dimers on Ge„001..
نویسندگان
چکیده
We report an ab initio study of the energetics and scanning tunneling microscopy ~STM! images of Si ad-dimers on Ge~001! and energetics of Ge ad-dimers on Si~001!. As in the case of Si dimers on Si~001!, we find for both systems that the D dimer configuration, lying between the substrate dimer rows and parallel to them, is highest in energy. Conversely, recent STM experiments for Si ad-dimers on Ge~001! deduce the D configuration to be most stable. Our theoretical STM images for this system find that both the D and C configurations ~the latter also between the rows! have similar STM images for the experimental voltages. We propose an experimental test ~low-bias STM imaging! which would unambiguously distinguish between the D and C configurations. @S0163-1829~99!04631-7#
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