Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 46: Low-Dimensional Systems: Molecular Conductors

TT 46.8: Vortrag

Dienstag, 1. April 2014, 15:45–16:00, HSZ 204

Electronic transport through defective carbon nanotubes — •Fabian Teichert¹, Andreas Zienert¹, and Jörg Schuster² — ¹Center for Microtechnologies, Technische Universität Chemnitz, Chemnitz, Germany — ²Fraunhofer Institute for Electronic Nano Systems, Chemnitz, Germany

Continuing the miniaturization, microelectronics will ultimately approach the atomic scale. One prominent example are carbon nanotubes (CNT), which could be used for transistors and interconnects. So far CNTs cannot be grown or deposited in an ideal and reproducible way inside a device. As one consequence they contain defects.

The present work aims to describe the transport properties of defective armchair CNTs. The focus is set on monovacancies and divacancies. The calculation of the transmission spectrum and the conductivity is done by a fast recursive equilibrium Green's function formalism, which scales linearly with the length of the tube, allowing to treat large systems. The electronic structure is described by the density functional based tight binding model. Single defects, double defects and the behavior of single configurations with many defects are studied. Furthermore, the mean influence of certain defect densities and the diameter of the CNT is investigated within a statistical analysis. It is shown that in the limit of small transmission the system is in the regime of strong localization, where the conductivity scales exponentially with the number of defects. Consequently, a localization length can be extracted, which depends on the defect density and on the CNT diameter.