[Pw_forum] Young's Modulus

[Stefano Baroni]

The application of linear response theory to the calculation of elastic constants implemented in abinit was introduced by Giannozzi, Testa, and myself soon after our paper on linear-response theory, back in 1987 (PRL 59m p. 2662), and rediscovered a few years ago in the abinit group. We never implemented our LRT approach because we always thought that, beside elegance, LRT had few advantages with respect to the brute-force calculation of the elastic constants. We may be wrong, and if anybody volunteers to implement this old idea of ours, I would be delighted to help. In any case, I would be curious to know if the "systematic" calculation of elastic constants in abinit is any faster than what you can get "by hands" either using QE. Cheers - SB

On Sep 22, 2010, at 3:45 PM, mohsen modaresi wrote:

> Dear Stefano, Eyvaz and Mike,
> Thanks for your reply. I follow this procedure and get Young's Modulus for CNT (3,3):
> 1) relax the structure.
> 2) compressed the structure in Z direction (parallel to the axis of nanotube) and calculate "Force" between atoms and then calculate the Young's Modulus by using it's definition (  E=(F/A)/((L-L0)/L0)  ). The result has "good" agreement with reported one. 
> But one of my friend work with Abinit. Abinit can calculate elastic constant in a systematic way.
> Dr. Eyvaz Isaev thanks for the link.
> 
>   
>     
> 
> On Tue, Sep 21, 2010 at 5:09 PM, Mike Mehl <Michael.Mehl at nrl.navy.mil> wrote:
> We've changed the link slightly.  It's now:
> 
> http://cst-www.nrl.navy.mil/users/mehl/papers/cij453.pdf
> 
> On 09/21/2010 08:44 AM, Eyvaz Isaev wrote:
> >
> > ------------------------------------------------------------------------
> > *From:* mohsen modaresi <modaresi.mohsen at gmail.com>
> 
> > See papers: Mehl et al., PhysRev.B 41, 10311, 1990 and Mehl et al, in
> > Intermetallic Compounds: Principles and Practice, vol.1, Principles,
> > J.H. Wesbrook and R.L. Fleischer, eds, John Wiley and Sons (London,
> > 1995), ch.9 (pp. 195-210).
> 
> --
> Michael J. Mehl
> Head, Center for Computational Materials Science
> Naval Research Laboratory Code 6390
> Washington DC
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> 
> 
> -- 
> Mohsen Modarresi,
> PhD student of Solid State Physics, Ferdowsi University of Mashhad, Iran.
> Phone +98-9133452131
> 
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center - Trieste
http://stefano.baroni.me [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

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