3C-SiC(001)-3×2 reconstructed surface analyzed by high-resolution medium energy ion scattering

• Published in: Surface science 2012-12, Vol.606 (23-24), p.1942-1947
• Main Authors: Matsuda, T., Tagami, M., Mitsuhara, K., Visikovskiy, A., Shibuya, M., Kido, Y.
• Format: Article
• Language: English
• Subjects: 3C-SiC-3 × 2 surface; Ab initio calculations; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Medium energy ion scattering (MEIS); Physics
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2012.08.021

The atomic structure of the 3C-SiC(001)-3×2 reconstructed surface was analyzed precisely by high-resolution medium energy ion scattering (MEIS). The present MEIS analysis unambiguously shows that the (3×2) surface consists of Si adatoms (1/3ML, 1ML=1.05×1015atoms/cm2) on top and underlying Si adlayer (2/3ML) on the bulk truncated Si plane. As the result, the most probable structure is focused on the Two Adlayer Asymmetric Dimer Model predicted by ab initio calculations and the modified versions with alternating long and short dimers in the 2nd adlayer proposed by photoelectron diffraction (PED) and by grazing incidence X-ray diffraction (GIXRD) analyses. Observed MEIS spectra are well reproduced by the structure relatively close to that determined by PED rather than GIXRD. Interestingly, the first principle calculations using VASP (Vienna ab initio simulation package) prefer symmetric dimers in the second Si adlayer and non-relaxed interplanar distance between the top Si and 2nd C plane of the bulk-truncated surface, which are, however, unable to reproduce the observed MEIS spectra. The distorted 2nd adlayer (asymmetric dimers) may correlate with the compressed interplanar distance between the underlying Si and C planes. The structure of 3C-SiC(001)-3×2 reconstructed surface is determined by high-resolution medium energy ion scattering. [Display omitted] ► High-resolution medium energy ion scattering coupled with ab initio calculations ► 3C-SiC(001)-3×2 surface consists of two Si-adlayers. ► Analysis using focusing and blocking effects ► The most probable structure comprises asymmetric dimers on top and alternating long and short dimers in the 2nd adlayer. ► The structure is close to that determined by photoelectron diffraction rather than the prediction by ab initio calculations.