The ABINIT Users Mailing List ( CLOSED )

[Nicola Marzari <marzari@MIT.EDU>]

paolajc@eden.rutgers.edu wrote:
> Dear all,
> Thank you very much for your previous feedback regarding the CNT structure.  I just have one question about using abinit to model carbon nanotubes.  Since these are 1D structures, is it possible to accurately obtain good results from abinit when modeling CNTs?  determining the total energy, elastic props, phonon dispersion,etc.  
>
> Thank you,
> Paola 


Dear Paola,

the short answer is yes - density-functional theory,
using a modern GGA approximation (or, for this case, even
LDA) works well in describing the structural and elastic
properties of sp2 (and sp3) carbon. Hence Abinit will work
well. Many authors have published on this, since the early '90s -
we also have some extensive calculations in a recent 2005 PRB.

Carbon nanotubes require very special care, and very high
accuracy, if you are interested in vibrational properties around
the Kohn anomaly (see the work of Mauri, PRL 2004 and 2005),
or the acustic dispersions very close to the Gamma point,
that are relevant for thermal expansion.

1d conductors are thought to have excitations that are quite
different from quasiparticles, and that are described by
a Luttinger liquid - for which evidence (with some controversy)
has been found in CNTs. That doesn't necessarily concerns
the quantities you are interested, and up to now all CNTs
calculations (including e.g. electron-phonon terms) have
been found in good agreement with expts.


                        nicola



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Prof Nicola Marzari   Department of Materials Science and Engineering
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