Defects, Quasibound States, and Quantum Conductance in Metallic Carbon Nanotubes

Hyoung Joon Choi(1), Steven G. Louie(2,3), Marvin L. Cohen(2,3), and Jisoon Ihm(1)

 

(1) School of Physics, Seoul Nantional University, Korea
(2) Department of Physics, University of California at Berkeley, USA
(3) Materials Sciences Division, Lawrence Berkeley National Laboratory, USA

The effects of impurities and local structural defects on the conductance of metallic carbon nanotubes are calculated using an ab initio pseudopotential method within the Landauer formalism.[1] Substitutionally doped boron or nitrogen produces quasibound impurity states of a definite parity and reduces the conductance by a quantum unit (2e2/h) via resonant backscattering. These resonant states show strong similarity to acceptor or donor states in semiconductors. The Stone-Wales defect also produces quasibound states and exhibits quantized conductance reduction. In the case of a vacancy, the conductance shows a much more complex behavior than the prediction from the widely used pi-electron tight-binding model.

Reference
[1] H.J. Choi, S.G. Louie, M.L. Cohen, and J. Ihm, PRL, v.84, p.2917 (2000).