[Pw_forum] energy of 33CNT

[Nicholas E. Singh-Miller]

Dear Zhu Xi,

I have not run your input file, but assuming that it is correct and this 
0.625eV is what you read directly from the output, this Fermi energy 
should also be correct.  If you are interested in the work function of 
the (3,3)CNT you will have to obtain the difference between a vacuum 
potential and the Fermi energy.  In short the potential in the vacuum != 0 
due to the use of periodic boundary conditions.  If you  use pp.x to 
obtain the potential remember that is is output in Rydbergs.   This is all 
discussed other times on the forum.

best of luck,

Nicholas

On Thu, 10 Jan 2008, Zhu Xi wrote:

> Dear users,
>
> I run a scf calculation of (3,3)CNT, but the fermi energy is 0.652eV, can
> anyone give some suggestion? thanks
>
> ====================================================================================
>
> &control
>         calculation='scf',
>         PSEUDO_DIR='./',
>         prefix='33',
>         forc_conv_thr=1.0D-4,
> /
> &SYSTEM
>         ibrav = 0,
>          celldm(1)= 18.8972612499,
>        nat = 12,
>         ntyp = 1,
>         ecutwfc = 40.0 ,
>         nosym = .true. ,
>         nbnd  = 48 ,
>   occupations= 'smearing',degauss = 0.001
>
> /
> &electrons
>        conv_thr    = 1.D-6,
>        mixing_beta = 0.5D0,
> /
> CELL_PARAMETERS
>     1.0    0.000000000    0.000000000
>     0.000000000    1.0    0.000000000
>     0.000000000    0.000000000     0.245951
> ATOMIC_SPECIES
>    C    12.00000  C.pz-vbc.UPF
> ATOMIC_POSITIONS (crystal)
> C        0.625289967   0.669611155   0.250000000
> C        0.487077242   0.709466388   0.250000000
> C        0.291384631    0.523168925   0.250000000
> C        0.374710033   0.330388845   0.750000000
> C        0.512922758   0.290533612   0.750000000
> C        0.708615369   0.476831075   0.750000000
> C        0.416429985   0.692001578    0.750000000
> C        0.675464001   0.616817067   0.750000000
> C        0.312292454   0.592869751   0.750000000
> C        0.583570015   0.307998422   0.250000000
> C        0.324535999   0.383182933   0.250000000
> C        0.687707546   0.407130249   0.250000000
> K_POINTS automatic
> 1 1 11 0 0 0
>
> ==================================================
>

*****************************************
Nicholas E. Singh-Miller
Ph.D. Candidate
Prof. Marzari Group (quasiamore.mit.edu)
Materials Science and Engineering
Massachusetts Institute of Technology
13-4066
(617)324-0372
*****************************************