2,314 research outputs found
Relation between dispersion lines and conductance of telescoped armchair double-wall nanotubes analyzed using perturbation formulas and first-principles calculations
The Landauer's formula conductance of the telescoped armchair nanotubes is
calculated with the Hamiltonian defined by first-principles calculations
(SIESTA code). Herein, partially extracting the inner tube from the outer tube
is called 'telescoping'. It shows a rapid oscillation superposed on a slow
oscillation as a function of discrete overlap length with an integer
variable and the lattice constant . Considering the interlayer
Hamiltonian as a perturbation, we obtain the approximate formula of the
amplitude of the slow oscillation as where is
the effective interlayer interaction and is the band split
without interlayer interaction. The approximate formula is related to the
Thouless number of the dispersion lines.Comment: 9 figure
Exciton Mott transition in Si Revealed by Terahertz Spectroscopy
Exciton Mott transition in Si is investigated by using terahertz time-domain
spectroscopy. The excitonic correlation as manifested by the 1s-2p resonance is
observed above the Mott density. The scattering rate of charge carriers is
prominently enhanced at the proximity of Mott density, which is attributed to
the non-vanishing exciton correlation in the metallic electron-hole plasma.
Concomitantly, the signature of plasmon-exciton coupling is observed in the
loss function spectra.Comment: 5 pages, 3 figure
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