AVS 50th International Symposium
    Applied Surface Science Monday Sessions
       Session AS-MoA

Paper AS-MoA9
Band Modulation in Various Nanopeapods and Its Origin

Monday, November 3, 2003, 4:40 pm, Room 324/325

Session: Nanotube and Nanoparticle Characterization
Presenter: J. Lee, Seoul National University, Korea
Authors: J. Lee, Seoul National University, Korea
H. Kim, Seoul National University, Korea
S.-J. Kahng, Korea University, Korea
J. Ihm, Seoul National University, Korea
H. Shinohara, Nagoya University, Japan
Y. Kuk, Seoul National University, Korea
Correspondent: Click to Email
Recent studies show interesting electronic properties of carbon nanotubes with various metallofullerenes. We have performed scanning tunnelling microscopy and spectroscopy study on these peopods.@footnote 1@ Two surprising characters were found: 1) large magnitude of the bandgap modulation (as large as ~1eV in Gd@sub 2@C@sub 92@ peapods and ~0.3eV in GdC@sub 82@ peapods) and 2) multiple oscillation of the conduction band edge in the position dependent spectroscopy near a defect. Our theoretical simulation results partly describe the main features in the experimental data. The modulation of band is caused by derived states from states of nanotube and metallofullerene. The conduction band oscillation was explained by many body screening effect around a defect. The observation of multiple fringe patterns near a potential barrier was predicted in the STM theory of Luttinger liquid near a perfect reflecting boundary,@footnote 2@ which expected a set of infinitely extending hyperbolars in the dI/dV(X,V) spectra. In the case of metallofullerene peapod, however, the finite barrier potential can result in curvilinear sub-bands surrounding the scattering potential. The current results imply that the transport properties of peapods may be dominated by the extent and strength of the scattering potential associated with the electronic structure of the inserted metallofullerenes. The recent transport measurement@footnote 3@ also supports our observation and calculation. A more detailed understanding of the phenomenon may require a many-body electron screening theory with e the pseudo-2D geometry and external potential. @FootnoteText@ @footnote 1@ Jhinhwan Lee, H. Kim, S.-J. Kahng, G. Kim, Y.-W. Son, J. Ihm, H. Kato, Z. W. Wang, T. Okazaki, H. Shinohara, and Young Kuk, Nature 415, 1005 (2002).@footnote 2@ Sebastian Eggert, Phys. Rev. Lett. 84, 4413 (2000)@footnote 3@ P.-W. Chiu, G. Gu, G.-T. Kim, G. Philipp, S. Roth, S.F. Fang, and S. Yang, Appl. Phys. Lett. 79(23), 3845-3847 (2001).