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Peculiarities of conductance of carbon nanotube‐based quantum dots
Author(s) -
Ogloblya O. V.,
Prylutskyy Yu. I.,
Strzhemechny Yu. M.
Publication year - 2010
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.22153
Subject(s) - zigzag , quantum dot , conductance , condensed matter physics , fermi energy , heterojunction , physics , carbon nanotube , fermi level , carbon nanotube quantum dot , coulomb blockade , nanotube , electron , quantum mechanics , materials science , nanotechnology , geometry , transistor , voltage , mathematics
Within the framework of the surface Green's function matching method, we carried out calculations of the differential conductance of symmetrically and asymmetrically connected armchair ( n, n )—zigzag (2 n , 0)—armchair ( n , n ) carbon nanotubes with different lengths of the middle section and infinitely long ends. It is shown that the ( n, n )/(2 n , 0)/( n, n ) segment, when n is not a multiple of 3, behaves as a quantum dot and has a conduction gap even for short middle segments. The position of the conductance peeks closest to the Fermi energy is determined by the interface states of the ( n, n )/(2 n , 0) junction. In addition to conductance peaks originating from the interface states of the ( n, n )/(2 n , 0) heterojunction, for sufficiently long middle zigzag nanotube, there are more conductance peaks in the vicinity of the Fermi energy, and those stem from the electronic structure of an individual finite (2 n , 0) zigzag nanotube. However, positions of the peaks farther away from the Fermi energy cannot be found in such a simple way. Thus, such ( n, n )/(2 n , 0)/( n, n ) quantum dot has singularities in its electronic properties, which may yield the Coulomb blockade effect should those strongly localized discrete levels become occupied. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010