Subband structure of carbon nanotubes: Difference between revisions

From phys824
Jump to navigationJump to search
(Created page with "==Tools== * [https://wiki.fysik.dtu.dk/ase/ase/structure.html Create GNR atom coordinates using ASE] ==Metallic (9,0) CNT using LCAO== *zgnr_lcao.py: <pre> from gpaw impor...")
 
Line 5: Line 5:
==Metallic (9,0) CNT using LCAO==
==Metallic (9,0) CNT using LCAO==


*zgnr_lcao.py:
*cnt9-0_lcao.py:


<pre>
<pre>
from gpaw import GPAW, FermiDirac
from ase import Atoms
from ase.io import read, write
from gpaw import GPAW, PoissonSolver, Mixer
from ase.structure import graphene_nanoribbon


</pre>


# -------------------------------------------------------------
==Semiconducting (10,0) CNT using LCAO==
# Bulk configuration
# -------------------------------------------------------------
 
zgnr = graphene_nanoribbon(8, 1, type='zigzag', saturated=True,
                            C_H=1.1, C_C=1.42086, vacuum=8.0,
                            magnetic=False, initial_mag=0.0)
 
zgnr.center()
write('zgnr.traj', zgnr)
 
 
# Make self-consistent calculation and save results
calc = GPAW(h=0.18,
            mode='lcao',
            xc='PBE',
            basis='szp(dzp)',
            kpts=(1,1,9),
            occupations=FermiDirac(width=0.05, maxiter=2000),
            mixer=Mixer(beta=0.010, nmaxold=8, weight=100.0),
            poissonsolver=PoissonSolver(eps=1e-12),
            txt='band_sc.txt')
 
zgnr.set_calculator(calc)
zgnr.get_potential_energy()
calc.write('band_sc.gpw')
 
 
# Calculate band structure along Gamma-X
from ase.dft.kpoints import ibz_points, get_bandpath
G = (0, 0, 0)
X = (0, 0, 0.5)
kpts, x, X = get_bandpath([G, X], zgnr.cell, 60)
 
calc = GPAW('band_sc.gpw',
            mode='lcao',
            xc='PBE',
            basis='szp(dzp)',
            kpts=kpts,
            txt='band_harris.txt',
            fixdensity=True,
            parallel={'domain': 1},
            usesymm=None,
            convergence={'bands': 'all'})
 
if calc.input_parameters['mode'] == 'lcao':
    calc.scf.reset()


calc.get_potential_energy()
calc.write('band_harris.gpw')
</pre>
*find_band_dat.py
<pre>
<pre>
from ase.lattice import bulk
from gpaw import GPAW
calc = GPAW('band_harris', txt=None)
import numpy as np
eps_skn = np.array([[calc.get_eigenvalues(k,s)
                    for k in range(60)]
                    for s in range(1)]) + 6.23712


for n in range(66):
    for k in range(60):
        print k, eps_skn[0, k, n]
    print
</pre>
</pre>

Revision as of 10:01, 2 November 2012

Tools

Metallic (9,0) CNT using LCAO

  • cnt9-0_lcao.py:

Semiconducting (10,0) CNT using LCAO