Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 115: Metallic Nanowires on the Atomic Scale (jointly with DS, O)
TT 115.1: Hauptvortrag
Freitag, 20. März 2015, 09:30–10:00, H 2032
From 2D to 1D: Honeycomb crystals and their nanoribbons — •Friedhelm Bechstedt — Friedrich-Schiller-Universitaet Jena, Germany
Metal-induced quantum wires are usually prepared on Si and Ge surfaces. Novel two-dimensional (2D) sheet crystals silicene, germanene and stanene as well as their functionalized counterparts are prototypes to study such atomically-thin layer systems.
Their exotic properties are studied using modern electronic-structure methods and discussed in the light of available experiments:
(i) Despite partial sp3-bonding Dirac cones appear in their band structure similar to the sp2-bonded graphene.
(ii) The infrared absorbance is given by the Sommerfeld fine-structure constant.
(iii) Chemical functionalization opens significant fundamental gaps. Excitons occur with giant binding energies.
(iv) A quantum spin Hall phase is due to spin-orbit interaction.
According to recent predictions one-dimensional structures, i.e., nanoribbons, should conduct electricity with 100% efficiency at room temperature with zero resistance along their edges. The predictions are critically discussed. The influence of magnetic ordering of edge states and external electric fields are investigated.