Topics

16

General Questions and Answers / Could I convert a Equivalent_bulk system into a two-probe system?

« on: November 9, 2009, 01:54 »

Hi, dear everyone
We can easily convert a two-probe system into a  bulk_configuration--bulk_configuration_Equivalent_bulk system ,and how can I convert a Equivalent_bulk system into a two-probe system?

Did someone have ideas and give me the workflow in detail?


Thanks a lot

17

General Questions and Answers / How can I bulid such two-probe system as the append files?

« on: November 7, 2009, 13:44 »

Hi,everyone:

    Could someone tell me how can I bulid such two-probe system as the append files? May be you should notice the chiral of nanotube.
If you accomplish the structure, Could you tell me the work-flow that you do ? If you build the two-probe system in other software, could you teach me how can I import the electrode and the central region from other software into ATK/vnkl correctly?

By the way . When  we put the central region or apice of nanotube into Molecular Builder, it rotate some angle(which is complex for nanotube's chiral  ), how can I solve the problem?


Thanks a lot!

18

General Questions and Answers / How can I solve the problem about geometric_constraints ?

« on: October 25, 2009, 05:57 »

I have build a two-probe system about Nanotube-gnr junctions ,and I have been optimized the electrode and the GNR separately .But when I optimize the two-probe constructure, the error about the geometric_constraints appears whenever the geometric_constraints is () or (0,1,)(the error message ---
file............line  in ?
geometric_constraints = ( )
ATKError: bad allocation

the append file is the script which has no elements and coordinates

How can I solve this problem ? Thanks a lot!

19

General Questions and Answers / My confuse about the work flow of restoreSelfConsistentCalculation() and scf?

« on: June 29, 2009, 15:34 »

Hi, I am confusing about the work flow of restoreSelfConsistentCalculation() and scf recently ,and I search the all the Forum and see the relevant topic, but found nothing, could some one tell me the correct idea about that?
This is the scriptof lih2li :

Code

from ATK.TwoProbe import *
import numpy
import ATK
# Restore two-probe geometry
vnlfile = VNLFile('lih2li.vnl')
lih2li = vnlfile.readAtomicConfigurations()['lih2li']
# Use the same parameters for final bias as for zero bias
bz_int_param = brillouinZoneIntegrationParameters(
monkhorst_pack_parameters=(1,1,100)
)
electrode_params = ElectrodeParameters(
brillouin_zone_integration_parameters = bz_int_param
)
basis_set_params = basisSetParameters(
type = SingleZeta,
element = Lithium
)
iteration_control_params = iterationControlParameters(
tolerance = 1e-5
)
ATK.setVerbosityLevel(0)
# Restore initial density from old calculation
scf = restoreSelfConsistentCalculation("lih2li-scf.nc")#.............................A
print '# Bias (Volt)\tCurrent (Ampere)'
# Run bias from 0.0 and 1.0 in steps of 0.1
for voltage in numpy.arange(0.0, 1.01, 0.1):
dft_method = TwoProbeMethod(
electrode_parameters=(electrode_params,electrode_params),
basis_set_parameters = basis_set_params,
iteration_control_parameters = iteration_control_params,
electrode_voltages = (voltage/2.0, -voltage/2.0)*Volt
)
# Store each calculation in a separate NetCDF file
ATK.setCheckpointFilename ('lih2li-bias-%.1f.nc' % voltage)#........................B
scf = executeSelfConsistentCalculation(
atomic_configuration=lih2li,
method = dft_method,
initial_calculation = scf                                               #...........................C
)
current = calculateCurrent(scf)
print "%.1f\t\t%.2e" %(voltage, current.inUnitsOf(Ampere))

my confuse is:
In the fist loop, at A line the .nc file is lih2li-scf.nc ,at B line we defined the .nc file as lih2li-bias-%.1f.nc ,then my question is that the .nc file I think is lih2li-bias-%.1f.nc ,is right ? and the lih2li-bias-%.1f.nc cover the lih2li-scf.nc or not? and at c line which .nc file pass to scf ?
 From A to B to C ,how the change of the .nc file ?and they how to work and pass ?

Thanks a lot

20

Future Releases / Could ATK compute the material's property and transport under magnetic field?

« on: June 25, 2009, 17:45 »

 I have saw many experiment that they measure the transport property under magnetic field? could we compute such case?

21

General Questions and Answers / How can we run the ATK programme in the bachground?

« on: June 13, 2009, 11:46 »

I successfully run the ATK programme in paralleling through ssh on the tele-computer with Mpich2-1.08. I have used mpd & commond and the ATK programme's paralleling is good,but it stop work when I close the window of ssh .How can I solve the problem?

22

General Questions and Answers / How can we get the band index of the bulk?

« on: June 10, 2009, 15:18 »

Hi,
we can get the quantum number of the molecular through computing it's Molecular energy spectrum,but when we put the bulk into the Nanolanguage Scripter,there has no energy spectrum in the Analysis. So how we can get the band index (quantum number of energy band)?And how we can know the band index corresponding which band in the band structure figure?

Thanks a lot!

23

Future Releases / My suggestion of improving on Moleculde Builder and Atomic Manipulator

« on: June 7, 2009, 17:28 »

First,could you add the function like translate and rotate in the Moleculde Builder :aline the central region 's principal moments of inertia on any direction and any coordinate as origin which you want? I think this may be easy to realization?

Second, could you add the function like translate the electrode   in the xy direction in the  Atomic Manipulator? may be it is also not hard?
Third,could you add the function that change the electrode' element? may be it is  hard in the Atomic Manipulatorbut easy in the script?

Thanks a lot!

24

General Questions and Answers / How to calculate the Fermi surface?

« on: April 20, 2009, 05:54 »

Hi,
  I am puzzled that how to calculate the Fermi surface with ATK,then plot the beautiful  figure of Fermi surface and it's projection figure for majority  and minority?
Could you help me?
 Thanks a lot!