[Pw_forum] reconstruction

[Marcel Mohr]

Dear Ali

You can start with (lateral) surface reconstruction of your bulk system. 
Afterwards I would try different supercells with different starting points, like 
number of atoms or "surface molecules". Don't forget to saturate dangling 
bonds (even there you can check different types). I think in Si NWs even a 
SiH3 group is outermost for some NWs
After relaxing your structures you can check the most favorable ones 
by comparing energies (have a look at surface calculations for details).
Good luck

Marcel Mohr
--
Institut für Festkörperphysik
TU Berlin



On Tue, 21 Apr 2009, Prasenjit Ghosh wrote:

> Dear Ali,
> 
> It depends on the type of reconstruction the surface of the nanowire undergoes.  May be if you tell a bit more about the type of reconstruction, I
> can tell you more.
> 
> Prasenjit.
> 
> 2009/4/21 ali kazempoor <kazempoor2000 at yahoo.com>
>       Dear Prasenjit
> Thank you for your reply, but I mean what I do to see the surface reconstruction at lateral nanowire surface. For simulation of a nanowire
> in z direction we add vaccum around nanowire in x and y and for z we use periodic boundary condition . So if we only suppose one unit
> repetation in z , we can not observe the surface reconstruction . Therefor for observing reconstruction , I think we have to make for
> example twice unit repetation in z or more.
> thanks
> 
> --- On Tue, 4/21/09, Prasenjit Ghosh <prasenjit.jnc at gmail.com> wrote:
>
>       From: Prasenjit Ghosh <prasenjit.jnc at gmail.com>
>       Subject: Re: [Pw_forum] reconstruction
>       To: "PWSCF Forum" <pw_forum at pwscf.org>
>       Date: Tuesday, April 21, 2009, 10:38 AM
> 
> 
> Dear Ali,
> 
> Usually when you speak of simulating a nanowire, because of the periodic boundary conditions, you simulate an infinite one. If the
> nanowire is aligned along Z axis, which seems to be your case,  then you have periodicity along the Z-direction. Therefore you need
> to  have enough vacuum along the x & y direction so that the periodic images should not interact.
> 
> Prasenjit.
> 
> 2009/4/20 ali kazempoor <kazempoor2000 at yahoo.com>
>
>       Dear all
>       I want to study the fingerprint of reconstruction in nanowire facets. How can  I find that wheater I have surface
>       reconstruction or not? Should I make a bigger supercell in Z direction( Z is the lenght of nanowire)?
>       thanks
>       Ali Kazempour.Isfahan University of Technology,Iran
> 
> 
>
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> 
> --
> PRASENJIT GHOSH,
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> --
> PRASENJIT GHOSH,
> POST-DOC,
> ROOM NO: 265, MAIN BUILDING,
> CM SECTION, ICTP,
> STRADA COSTERIA 11,
> TRIESTE, 34104,
> ITALY
> PHONE: +39 040 2240 369 (O)
>              +39 3807528672 (M)
> 
>