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Atomic and electronic structure of β − SiC ( 001 ) − ( 3 × 2 )

1999; American Physical Society; Volume: 60; Issue: 4 Linguagem: Inglês

10.1103/physrevb.60.2495

1095-3795

Wenchang Lu, Peter Krüger, J. Pollmann,

Semiconductor materials and devices

A reconstruction model for the cubic $\mathrm{SiC}(001)\ensuremath{-}(3\ifmmode\times\else\texttimes\fi{}2)$ surface, which we call two adlayer asymmetric-dimer model (TAADM), is suggested on the basis of ab initiopseudopotential total energy and grand canonical potential calculations. Within this model, two Si adlayers with a nominal total coverage of one monolayer are adsorbed on the clean Si-terminated surface. Asymmetric dimers are formed in the top adlayer with a dimer-bond length of 2.24 \AA{}. This reconstruction model overcomes all shortcomings of previous models, such as the single-dimer-row, alternate-dimer-row, and double-dimer-row models, and it is the most stable structure among all configurations which we have considered. The calculated surface-band structure, as well as the filled- and empty-state scanning tunneling microscope images for our TAADM, are in very good agreement with experimental observations.