Special Condensed Matter Physics Seminar

Thursday, March 9, 2000, 12:30 p.m.
Plant Sciences Building, Room 1117

Carbon Nanotube Wires and Junctions

Zhen Yao

(Delft University of Technology, The Netherlands)

Abstract:  Single-wall carbon nanotubes are single graphene sheets rolled up into nanometer-diameter cylinders that can be either one-dimensional metals or semiconductors, depending on how the sheets are rolled up.  An intramolecular junction seamlessly connecting two tube segments with different atomic and electronic structures can be created by introducing a pentagon and a heptagon into the hexagonal carbon lattice.  I will discuss electrical transport measurements of these fascinating wires and junctions connected to nanofabricated metal electrodes.  Individual metallic nanotubes appear to be able to carry remarkably high current densities exceeding a gigaampere per square cm without breaking down.  I will discuss the underlying phonon-scattering mechanism leading to the current saturation observed at high electric fields.  A metal-semiconductor intramolecular junction behaves as the world's smallest rectifying diode.  In the case of a metal-metal junction, the conductance seems to be strongly suppressed and it displays a power-law dependence on temperature and voltage, consistent with tunneling between the ends of two one-dimensional correlated electronic states, so-called Luttinger liquids.  I will also discuss electronic devices created by mechanical deformation.

Host: Ellen Williams

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