Dresden 2009 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 26: Nanostructured Materials I

MM 26.3: Vortrag

Mittwoch, 25. März 2009, 10:45–11:00, IFW B

A structure-induced metal-insulator transition in thin MoS nanowires — Igor Popov¹, Gotthard Seifert¹, and •Sibylle Gemming² — ¹Theoretische Chemie, TU Dresden, D-01062 Dresden, Germany — ²Forschungszentrum Dresden-Rossendorf, P.O.Box 510119, D-01314 Dresden, Germany

Transition metal chalcohalides MX2 can form a wealth of diverse nanostructures, which range from large octahedral and fullerene-like hollow clusters and cylindrical nanotubes close to the nominal composition M:X = 1:2 to smaller, two-dimensional platelet-shaped clusters under sulfur excess and to one-dimensionally elongated nanowires under sulfur-deficient conditions. All of those structures exhibit specific electronic properties that differ from the ones of the pure bulk and open up a large application spectrum, that includes the lubricant aspect, but extends to catalysis and electronic transport. One-dimensionally delocalized electronic states provide the basis for the higher activity, reactivity and conductivity in such nanostructures. One-dimensional MX wires are composed of a central metallic wire coated by a sulfur and/or halide shell. They exhibit a very high structural regularity, hence, ballistic conductivity may be obtained in such structures. DFT calculations showed that wires can act as electromechanical switches, because they undergo a symmetry-dependent metal-insulator transition upon twisting [Nano Lett.,10.1021/nl801456f; Nano Lett., 2008, 8, 3928-3931].