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Molecular ring transistors: Topology and structure
G. Cuniberti , J. Yi, M. Porto
Workshop on ``Quantum dynamical concepts: from diatomics to biomolecules''
2002.04.15-19; Dresden, Germany
| We investigate the rectification characteristics of a
carbon nanotube (CNT) ring transistor contacted by CNT
leads, whose novel properties have been recently
communicated by Watanabe et al. [Appl. Phys. Lett. 78,
2928 (2001)]. Our numerical results are validated by
the experimental observations. Moreover, we report on
additional features of the transmission of the CNT ring
device which are associated with the possibility of
breaking the lead inversion symmetry. The linear
conductance displays a ``chessboard''-like behavior
alternated with anomalous zero-lines which should be
directly observable in experiments. By studying a
one-dimensional ring displaying broken
inversion-symmetry as a simplified version of this
system, which allows for analytical treatment, we are
able to discriminate structural properties
(quasi-onedimensional confinement) from pure
topological effects (ring configuration). In the
simplified system, jumps in the transmittance phase
occur in correspondence to both (a) the zeros in the
transmission at the eigenstates of the isolated ring
(which lead to a discrete set of singular states in the
density of states) and (b) the destructive interference
events.
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Prof. Dr. Gianaurelio Cuniberti
secretariat:
postal address:
Institute for Materials Science
TU Dresden
01062 Dresden, Germany
visitors and courier address:
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