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Electrical Switching in Carbon Nanotubes and Conformational Transformation of Chain Molecules. 2006. 8. 30. Jisoon Ihm School of Physics, Seoul National University. Collaborators. Sangbong Lee, Seungchul Kim, Byoung Wook Jeong (Seoul Nat’l Univ.)
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Electrical Switching in Carbon Nanotubes and Conformational Transformation of Chain Molecules
2006. 8. 30
School of Physics, Seoul National University
Boron or Nitrogen
Band structure of a (10,10) single-wall nanotube ( LDA, first-principles pseudopotential method )
Similarity to acceptor states in semiconductors
H.J. Choi et al, PRL 84, 2917(2000)
Similarity to donor states in semiconductors
( Y.-W. Son, J. Ihm, etc., Phys. Rev. Lett. 95, 216602(2005) )
C. Dekker, A. Zettl
Is it possible to control the conductance of metallic single-wall carbon nanotubes?
S.B. Lee, A. Zettl
Interplay between defects and electric fields
: Landauer formalism
SCattering-state appRoach for eLEctron Transport (SCARLET)
H. J. Choi et al, PRB 59, 2267(1999), and in preparation
The electronic potential of N(B) is lowered. Levels of quasibound states move down.
The electronic potential of N(B) is raised. Levels of quasibound states move up.
3. B(N) doped (10,10) SWNT
∆H ∝ Eext · (diameter)2
Quasibound states move up or down depending on the direction of Eext.
( B.-Y. Choi et al., Phys. Rev. Lett. 96, 156106(2006) )
(Voltage bias using STM)
Importance of geometric symmetry (equilateral triangle)
Doubly degenerate impurity states cause perfect reflection at 0.6 eV.
(Both even and odd states are fully reflected at same energy.)
Eigenstate |ψ> of Htot associated with the eigenstate |> of H0 with the same energy E (with impurity potential U at site a)
Reflection for the specific state |> :
Total transmission :
Resonance condition :
: G0 projected at site a
With applied electric fields,
Suppose ∆H at site α is ∆E.
In other words, is G0(α;E) shifted by ∆E.
(10,10) SWNT with NO Eext while changing the strength of the attractive potential, U.
EFChanging Eext is different from changing U.
(10,10) SWNT with a single attractive impurity of U=-5|t| while changing Eext
Canon-Toshiba SED at CEATEC2004