Teoretické výpočty interakce adsorbátu s orientovanými povrchy Si

Krejčí, Ondřej

In this work I briefly described the basic ideas of density functional theory (DFT) for calculations of an electronic structure of molecules, solids and surfaces. I also summarized the fundamentals of DFT based Fireball code that was used for calculations of the atomic and electronic structures of several models. Fur- ther I described theory of scanning tunnelling microscopy (STM) and mentioned some approaches of simulating STM maps by means of results of DFT calcula- tions. The studied models were reconstructions of a Si (111) surface, namely the 7×7, 2×1 Pandey chain and reconstructions with periodicity √ 3 × √ 3, where finding proper atomic structure, fitting to a new experimental observations, was required. I compared energetic favourableness of the reconstructions. I also stud- ied an adsorption of benzene on 7×7. I have analysed the atomic and electronic structure of all the models and made STM simulations using STM code. I com- pared the results with experimental STM maps in literature and with results of the STM experiments made by RNDr. Pavel Kocán, Ph.D. (reconstruction v √ 3 × √ 3) and by Prof. Alastair McLean (benzene on 7×7). Probable model of observed metastable reconstruction √ 3 × √ 3 was found. The proof that benzene chamisorbate in so called di-σ-bridge position was also made. 1

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