[Pw_forum] example of cnt

[Giovanni Cantele]

a CNT is represented, within QE, with the supercell approach, for example you choose a tetragonal cell, with z axis as a periodicity direction and x and y axes where vacuum space is added to
the lattice parameter(s) to prevent periodi replicas to interact with each other.

The positions of the C atoms for a nanotube of given diameter must be independently generated, I remember there are several scripts/tools available on line.

As an example, that should represent a (5,5) CNT (in this case an orthorhombic cell is considered):
 &CONTROL
        calculation='relax'
        title='C'
        restart_mode='from_scratch'
        nstep=100
        tprnfor=.true.
        outdir='./tmp'
        prefix='C'
        disk_io='default'
        pseudo_dir='/data/CODES/PWSCF/pseudo/'
 /
 &SYSTEM
        ibrav=6
        a=13
        b=13
        c=2.4941531628
        nat=20
        ntyp=1
        ecutwfc=30.0
        ecutrho=180.0
 /
 &ELECTRONS
 /
 &IONS
 /
ATOMIC_SPECIES
        C     12.011     C.pbe-van_bm.UPF
ATOMIC_POSITIONS { Angstrom }
C          3.4377467707          .0000000000          .0000000000
C          3.1405379467          1.3982575809          0
C          1.0623221745          3.2694914673          .0000000000
C          -.3593423864          3.4189144339          0
C          -2.7811955595          2.0206568529          .0000000000
C          -3.3626237555          .7147477439          0
C          -2.7811955599          -2.0206568526          .0000000000
C          -1.7188733856          -2.9771760345          0
C          1.0623221739          -3.2694914676          .0000000000
C          2.3003015802          -2.5547437243          0
C          2.7811955595          2.0206568526          1.2470765814
C          1.7188733853          2.9771760349          1.2470765814
C          -1.0623221742          3.2694914676          1.2470765814
C          -2.3003015806          2.5547437240          1.2470765814
C          -3.4377467707          0          1.2470765814
C          -3.1405379470          -1.3982575806          1.2470765814
C          -1.0623221745          -3.2694914673          1.2470765814
C          .3593423861          -3.4189144339          1.2470765814
C          2.7811955592          -2.0206568533          1.2470765814
C          3.3626237552          -.7147477443          1.2470765814
K_POINTS { automatic }
1  1  2    1  1  1

> On 27 Jan 2017, at 15:42, Uttam Paliwal <uttamphy at gmail.com> wrote:
> 
> 
> hi 
> is there any example to compute scf and nscf calculations of any kind of simple Carbon nanotube in QE. If there is any archive then please suggest how to construct a simple CNT in QE.
> -- 
> Uttam Paliwal
> Assistant Professor
> Department of Physics
> J.N.V. University
> Jodhpur (India)
> Phone- 7597908441
> _______________________________________________
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-- 

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at spin.cnr.it
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: http://people.na.infn.it/~cantele

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