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TT: Tiefe Temperaturen
TT 16: Postersitzung II: Amorphe und Tunnelsysteme, Mesoskopische Systeme, Schwere Fermionen, Kernmagnetismus
TT 16.10: Poster
Tuesday, March 27, 2001, 14:30–17:00, Rang S\ 3
Electronic Transport in Small Metallic Clusters — •Rafael Gutierrez, Frank Grossmann, and Rüdiger Schmidt — Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany
We study the electronic transport properties of one-dimensional sodium wires as well as two- and three-dimensional sodium clusters NaN (N=4⋯ 9) attached to two electronic reservoirs. Our calculations are based on the Landauer formalism combined with an approximate density-functional approach. For the wires there exists a critical electrode-wire separation below which the single atom shows a larger resistance than the Na-dimer, confirming recent ab initio calculations [N. D. Lang, Phys. Rev. Lett. 79, 1357 (1997)]. In our approach, this anomalous behaviour is shown to be dependent on the level of description of the wire (number of basis functions per atom) as well as on the strength of the electrode-wire coupling. For the NaN clusters the dependence of the resistance on the electrode-cluster separation and on the cluster orientation is investigated. For a given cluster size N, the resistance depends sensitively on the cluster geometry (isomers). As a function of cluster size, an even-odd oscillation of the minimal resistance is found.