[Pw_forum] Saw tooth potential details
mohamed sabri majdoub
majdoub at gmail.com
Wed Dec 16 23:24:16 CET 2009
Dear users,
I was reading the documentation for the saw tooth like potential in pwscf.
However, I still did not understood it in full. Can anybody gives me more
details about how the potential is implemented.
I need to apply an electric field to a supercell of graphene and BN layers
with both ends in vacuum. eamp = 0.002.
Amplitude of the electric field (in a.u. = 51.44 10^10 V/m )
The sawlike potential increases with slope "eamp" in the
region from (emaxpos+eopreg-1) to (emaxpos), then decreases
to 0 until (emaxpos+eopreg), in units of the crystal
vector "edir". Important: the change of slope of this
potential must be located in the empty region, or else
unphysical forces will result. Used only if tefield is .TRUE.
The following keywords that need to be used are still not clear. In
particular the position of the slope change.Does it need to be in vacuum?
emaxpos=0.5 (Position of the maximum of the sawlike potential along
crystal axis
"edir"); eopreg=0.5 (Zone in the unit cell where the sawlike potential
decreases.)?
How the sawlike potential is modeled.
Thank you in advance for your help and comment.
Here is the system I want to apply electric field to it:
&control
title = 'GphBN'
calculation = 'relax'
outdir = '/pwscf/pwscftemp/relaxGphBN'
prefix = 'GphBN'
pseudo_dir = /pwscf/input/Gph-BN/pseudopot-C-B-N'
verbosity = 'high'
tprnfor = .t.
restart_mode = 'from_scratch'
/
&system
ibrav = 0,
celldm(1) = 1.8897261
nat = 72,
ntyp = 3,
ecutwfc = 25.0
ecutrho = 250.0
occupations = 'smearing'
smearing = 'gaussian'
degauss = 0.003675
/
&electrons
mixing_beta = 0.05
diagonalization = 'david'
/
&ions
trust_radius_ini = 0.10
/
&cell
ATOMIC_SPECIES
B 10.81100 B.pz-vbc.UPF
C 12.01070 C.pz-vbc.UPF
N 14.00674 N.pz-vbc.UPF
ATOMIC_POSITIONS angstrom
B 0.710000 8.607000 11.306000
B 0.710000 11.066000 11.306000
B 2.840000 7.377000 11.306000
B 0.710000 6.148000 11.306000
B 6.390000 6.148000 8.000000
B 6.390000 8.607000 8.000000
B 6.390000 11.066000 8.000000
B 2.840000 9.836000 11.306000
B 7.100000 7.377000 11.306000
B 7.100000 9.836000 11.306000
B 7.100000 12.295000 11.306000
B 4.970000 11.066000 11.306000
B 2.840000 12.295000 11.306000
B 4.970000 6.148000 11.306000
B 4.970000 8.607000 11.306000
B 4.260000 7.377000 8.000000
B 2.130000 11.066000 8.000000
B 2.130000 8.607000 8.000000
B 2.130000 6.148000 8.000000
B 4.260000 9.836000 8.000000
B 0.000000 7.377000 8.000000
B 0.000000 9.836000 8.000000
B 4.260000 12.295000 8.000000
B 0.000000 12.295000 8.000000
C 2.130000 6.148000 14.612000
C 2.130000 8.607000 14.612000
C 2.130000 11.066000 14.612000
C 0.000000 12.295000 14.612000
C 0.000000 9.836000 14.612000
C 0.000000 7.377000 14.612000
C 0.710000 11.066000 14.612000
C 0.710000 8.607000 14.612000
C 0.710000 6.148000 14.612000
C 6.390000 8.607000 14.612000
C 6.390000 6.148000 14.612000
C 4.970000 11.066000 14.612000
C 6.390000 11.066000 14.612000
C 7.100000 12.295000 14.612000
C 7.100000 9.836000 14.612000
C 7.100000 7.377000 14.612000
C 4.970000 8.607000 14.612000
C 2.840000 12.295000 14.612000
C 2.840000 9.836000 14.612000
C 2.840000 7.377000 14.612000
C 4.260000 7.377000 14.612000
C 4.970000 6.148000 14.612000
C 4.260000 12.295000 14.612000
C 4.260000 9.836000 14.612000
N 0.000000 12.295000 11.306000
N 0.000000 9.836000 11.306000
N 0.000000 7.377000 11.306000
N 2.840000 7.377000 8.000000
N 2.840000 9.836000 8.000000
N 2.840000 12.295000 8.000000
N 4.970000 11.066000 8.000000
N 4.970000 8.607000 8.000000
N 4.970000 6.148000 8.000000
N 7.100000 12.295000 8.000000
N 7.100000 9.836000 8.000000
N 7.100000 7.377000 8.000000
N 0.710000 6.148000 8.000000
N 0.710000 8.607000 8.000000
N 0.710000 11.066000 8.000000
N 6.390000 11.066000 11.306000
N 6.390000 8.607000 11.306000
N 6.390000 6.148000 11.306000
N 2.130000 11.066000 11.306000
N 2.130000 8.607000 11.306000
N 2.130000 6.148000 11.306000
N 4.260000 12.295000 11.306000
N 4.260000 9.836000 11.306000
N 4.260000 7.377000 11.306000
K_POINTS automatic
10 10 1 1 1 0
CELL_PARAMETERS
8.51980 0.00000 0.00000
0.00000 7.37600 0.00000
0.00000 0.00000 22.6120
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