Berlin 2005 – wissenschaftliches Programm

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M: Metallphysik

M 32: Poster TU B (Symposium Tomographic Methods in Materials Research M-32.32-55)

M 32.8: Poster

Montag, 7. März 2005, 14:30–16:30, Poster TU B

Electronic structure of Ga₈₄ cluster compounds — •Johannes Frenzel, Sibylle Gemming, and Gotthard Seifert — Institut für Physikalische Chemie, TU Dresden, D-01062 Dresden

Semi-conducting and metal clusters as building blocks for organised structures are potential candidates for devices in nano electronics. In this field various aluminium and gallium clusters where synthesized with [Al₇₇(N(SiMe₃)₂)₂₀]²⁻ and [Ga₈₄(N(SiMe₃)₂)₂₀]⁴⁻ as the largest ones of this kind. Density functional calculations were carried out to study large bare and ligated gallium clusters and their packing in a three-dimensional crystal structure. In the single clusters, the electronic states are delocalised over the whole cluster and the gallium atoms exhibit no noticeable charge. Band structure calculations of the crystal do not yield any significant dispersion of the electronic bands. Thus it is concluded that the observed macroscopic electric conductivity is mediated by a hopping mechanism between the clusters rather than by the presence of states, which are delocalised over the whole crystal.