Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 18: Superconductivity: Borides, Borocarbides, Carbides, ...
TT 18.7: Vortrag
Dienstag, 28. März 2006, 16:45–17:00, HSZ 02
Lattice dynamics and electron-phonon interaction in doped small radius nanotubes — •K.-P. Bohnen1, R. Heid1, H.J. Liu2,3, and C.T. Chan2 — 1Forschungszentrum Karlsruhe, Institut für Festkörperphysik — 2Dept. of Phys., Univ. of Sci. and Technology, Kowloon, HongKong — 3Dept. of Phys., Wuhan Univ., Wuhan, People’s Republic of China
Recently lattice dynamics of small radius nanotubes has received a lot of attention due to the competition between superconductivity and Peierls transition. So far all ab-initio calculations for isolated nanotubes with diameter of 4 Å have shown a strong tendency to either a Peierls transition (in (3,3)-tubes)[1] or a structural transition to a non-metallic state with a small gap ((5,0)-tube) [2], in contrast to experimental findings of superconductivity in 4 Å tubes [3]. Doping these tubes might offer a possibility to enhance superconductivity, an effect which is well known from intercalated graphite. We present here ab-initio calculations of the lattice dynamics and electron-phonon coupling for doped (3,3)-tubes. The doping level has been chosen to move the Fermi level to a region of high density of states, however so far these calculations still favor the Peierls transition compared to superconductivity.
[1] K.-P. Bohnen, R. Heid, H.J. Liu, C.T. Chan, PRL 93, 245501 (2004)
[2] D. Connetable et al., PRL 94, 015503 (2005)
[3] Z.K. Tang et al., Science 292, 2462 (2001)