Showing papers by "Viktor Zólyomi published in 2002"
TL;DR: In this article, the behavior of the disorder-induced D band in the Raman spectrum of single-wall carbon nanotubes (SWCNTs) was investigated both theoretically and experimentally.
Abstract: The behavior of the disorder-induced D band in the Raman spectrum of single-wall carbon nanotubes (SWCNT's) was investigated both theoretically and experimentally. The measured maximum position of the D band for SWCNT bundles exhibits an oscillation superimposed on a linear shift, when the laser excitation energy ${E}_{\mathrm{laser}}$ varies in the range of 1.6--2.8 eV. We have shown theoretically by explicit integrations for the resonant Raman cross section that the D-band intensity of an isolated SWCNT has a sharp maximum when ${E}_{\mathrm{laser}}$ of either the incoming or the scattered photon matches a van Hove singularity in the joint density of states. This ``resonance'' must be considered in addition to the double resonance from a scattering by an impurity. Calculating the D band of a superposition of all the 114 SWCNT's within a given diameter range, both the shift and the oscillation in the experimentally observed spectra were reproduced.
151 citations
TL;DR: In this article, the double resonance theory was used to investigate the correspondence between the Stokes and anti-Stokes Raman D band of graphitic materials in general, and bundles of single-wall carbon nanotubes (SWCNT's) in particular.
Abstract: The correspondence between the Stokes and anti-Stokes Raman D band of graphitic materials in general, and bundles of single-wall carbon nanotubes (SWCNT's) in particular is investigated using the double resonance theory. The D band of bundles of SWCNT's is determined by the Van Hove singularity enhanced double-resonant Raman-scattering processes. We show that the experimentally observed 7--8 ${\mathrm{cm}}^{\ensuremath{-}1}$ difference between the Stokes and anti-Stokes D band--corresponding to the energy of one phonon---can be fully explained by the double-resonant Raman-scattering processes.
33 citations
02 Oct 2002-Structural and Electronic Properties of Molecular Nanostructures. XVI International Winterschool on Electronic Properties of Novel Materials
TL;DR: In this article, the D and D* bands of single wall carbon nanotubes (SWCNTs) were investigated theoretically and experimentally, and the measured peak positions vs. laser excitation energy (Elaser) exhibit an oscillation superimposed on a linear shift.
Abstract: The disorder induced D band and its overtone, the D* band (not disorder induced, sometimes also called G’) in the Raman spectrum of single wall carbon nanotubes (SWCNTs) were investigated theoretically and experimentally. The measured peak positions vs. laser excitation energy (Elaser) exhibit an oscillation superimposed on a linear shift. We have shown theoretically that the D‐band intensity of an isolated SWCNT has a sharp maximum when Elaser of either the incoming or the scattered photon matches a van Hove (vH) singularity in the joint density of states. Calculating the D and D* bands of a bundle of over 100 different SWCNTs both the shift and the oscillation in the experimental spectra were reproduced.
1 citations