460 research outputs found
Schottky barriers at metal-finite semiconducting carbon nanotube interfaces
Electronic properties of metal-finite semiconducting carbon nanotube
interfaces are studied as a function of the nanotube length using a
self-consistent tight-binding theory. We find that the shape of the potential
barrier depends on the long-range tail of the charge transfer, leading to an
injection barrier thickness comparable to half of the nanotube length until the
nanotube reaches the bulk limit. The conductance of the nanotube junction shows
a transition from tunneling to thermally-activated transport with increasing
nanotube length
A non-equilibrium equation-of-motion approach to quantum transport utilizing projection operators
We consider a projection operator approach to the non-equilbrium Green
function equation-of-motion (PO-NEGF EOM) method. The technique resolves
problems of arbitrariness in truncation of an infinite chain of EOMs, and
prevents violation of symmetry relations resulting from the truncation. The
approach, originally developed by Tserkovnikov [Theor. Math. Phys. 118, 85
(1999)] for equilibrium systems, is reformulated to be applicable to
time-dependent non-equilibrium situations. We derive a canonical form of EOMs,
thus explicitly demonstrating a proper result for the non-equilibrium atomic
limit in junction problems. A simple practical scheme applicable to quantum
transport simulations is formulated. We perform numerical simulations within
simple models, and compare results of the approach to other techniques, and
(where available) also to exact results.Comment: 16 pages, 5 figure
Born Oppenheimer Dynamics Near Metal Surfaces
We discuss the usefulness of Born-Oppenheimer potential surfaces for nuclear
dynamics for molecules strongly coupled to metal surfaces. A simple model
demonstrating the construction of such surface for a molecular junction is
discussed.Comment: 5 pages, 2 figure
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