Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 10: Elektronische Struktur II

O 10.7: Vortrag

Montag, 24. März 2003, 16:30–16:45, FOE/ORG

Different ordering of surface dimers and their influence on the band structure of Si(100) — •Philipp Eggert, Arno Schindlmayr, and Matthias Scheffler — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin-Dahlem

It is now believed that the Si(100) surface is formed of buckled dimers (DFT, QMC). Nevertheless the precise orientation of the dimers at different temperatures still requires more investigation.

One possible way to determine the actual ordering of the dimers is the comparison of angle resolved photoemission or two-photon photoemission data with calculated band structures. Therefore we present directly comparable ab initio band structure calculations for different reconstructions of the Si(100) surface. In particular we analyse how different ordering of the buckled dimers changes the band structure.

We calculate the band structures by performing fully converged self-energy calculations within the GW approximation, using the space-time approach. Starting from the (2×1) reconstruction, where all dimers are buckled in the same direction, we compare the band structure with the (2×2) reconstruction, where dimers in the same row are alternatingly buckled. To analyse the interaction of dimers in different rows, we also calculate the band structure of the c(4×2) reconstruction, where alternations in the dimer orientations are extended to neighbouring rows. By folding the band structure of the three different unit cell into the same Brillouin zone we can directly assess the effect of the dimer orientations.