Topics

1

General Questions and Answers / HELP! Can we consider the Coulomb interaction in the ATK?

« on: March 5, 2011, 02:50 »

Hello,everyone,

The physics origin of magnetism is the Coulomb interaction, if it does not take the Coulomb interaction into account, how can we valid the calculated results?

So in the ATK calculation, is it necessary to consider the coulomb interaction? And how induce the coulomb interaction in the DFT calculations?

What is the effect on magnetism when we consider the Coulomb interaction explicitly?

And could anybody provide me some references about the effects?

Thank you,these questions have puzzled me a long time, please help me.

2

General Questions and Answers / Problem with equivalent atoms

« on: May 1, 2010, 14:31 »

Hi,
i have a script 8.py for the two probe configuration.
when i drop the script to the Result Browser, two configuration 8.png looks well. when you drag the script into Atomic Manipulator first and then drag into either Result Browser or Nanolanguage Scripter,yuo will see thetwo configuration is wrong 81.png. i find the issue is on the equivalent_atoms.
the script is correct or not?
moreover, i have the same problem when i run the script 8cbn.py:
# TwoProbe Calculation
# ----------------------------------------------------------------
# sc  0 : q =  172.73989 e
Traceback (most recent call last):
  File "<string>", line 299, in ?
ATKError: inverse(DZMatrix const &) : Could not LU factorize!\
what can i do?

3

General Questions and Answers / how can we set the "initial_scaled_spin" reasonably for our calculation.

« on: April 10, 2010, 13:56 »

Hi

I am confused with setting the value of the "initial_scaled_spin" for the spin-polarized calculation.
Does the different value for the initial_scaled_spin will effect the last  result ,such as the DOS or transmission?Is there any difference with the calculation between  the initial_scaled_spin =0 and 1(-1) for the reslut,besides the speed of  computing.
what is the reasonable understanding of the initial_scaled_spin in our calculation? which physical quantity should we caluate or analyse before?
If for the unhomogeneoustwo-probe system, can we set the uniform value for different atoms? is that correct? if we can not ,what is the Process for we get the initial_scaled_spin?
In a word, i want to know how can set the correct and reasonable value for initial_scaled_spin for any system.

Need your help

4

General Questions and Answers / How can we get the magnetic moment of each atoms from MullikenPopulation?

« on: August 29, 2009, 12:02 »

 Hi,
i have got the MullikenPopulation,
 -----------------------------------------------------------------------------
# Mulliken Population
# -----------------------------------------------------------------------------
# Index      Population (Up,Down)
    c       0   (  1.8061 ,  2.0663 )
    c       1   (  2.0075 ,  1.9499 )
    c       2   (  1.9609 ,  2.0365 )
    c       3   (  2.0253 ,  1.9804 )
    c       4   (  1.9804 ,  2.0253 )
    c       5   (  2.0365 ,  1.9609 )
    c       6   (  1.9499 ,  2.0075 )
    c       7   (  2.0663 ,  1.8061 )
    H       8   (  0.5873 ,  0.5797 )
    H       9   (  0.5797 ,  0.5873 )
how can i get the magnetic moment of each atoms ,the system is the unit cell of zigzig carbon nanoribbon.
Thanks.

5

General Questions and Answers / how can we set the value of " initial_scaled_spin"

« on: August 25, 2009, 11:24 »

hi everyone,
    i mean if we want to calculate the spin depended properties.so we should give an initial spin to the structure.i am confused with the  value of " initial_scaled_spin" .just like the tutorial show the graphene ribbon initial_scaled_spin = [ 1., 1., 0., 0., 0., 0., -1., -1., 0., 0. ].i do not know why he setlike this.and if i set the value as initial_scaled_spin = [ 1., 0., 0., 0., 0., 0., 0., -1., 0., 0. ]orinitial_scaled_spin = [ 1., -1., 0., 0., 0., 0., 1., -1., 0., 0. ].is that ok? i want to know what does the initial_scaled_spin mean.
thank for your help.

6

General Questions and Answers / why?

« on: June 3, 2009, 13:32 »

why the ldos of pefect graphene nanoribbon is not periodically?
in my opinion, the pefect graphene nanoribbon is periodically,so its ldos should also periodically.but the ldos i got is not periodically as i have attched.

7

General Questions and Answers / ATKError

« on: June 2, 2009, 06:49 »

i want to calculate the dos ,while i have optimized the structure. i have saved an opt.nc file in the optimize.and i used the initial density by restoring the opt.nc,also i save anther checkpoint file dos.nc.and it does not work for the error:
Traceback (most recent call last):
  File "111spin-trans.py", line 345, in ?
    runtime_parameters = runtime_parameters
ATKError: inverse(DZMatrix const &) : Could not LU factorize!
what can i do ?
and i have some  other questions :
should i have to save the nc file of each calculation? or is it necessary for optimize?
is the nc file of opt equal to the nc file of scf?because we want to use the scf.nc file for farther calculation like the calculation of dos.i think may be it can save time of calculation.

8

General Questions and Answers / question about calculate the local_density_of_states

« on: May 24, 2009, 05:12 »

Hi:
i want to calculate the local_density_of_states of the structure that one fe atom adsorb on the graphene nanoribbon
part of my script is as follows:
local_density_of_states = calculateLocalDensityOfStates(
    self_consistent_calculation = scf,
    energy = 0.0*electronVolt,
    quantum_number = ((0.0,0.0),Spin.Up),
    green_function_infinitesimal = 1.0e-5*electronVolt
)
if processIsMaster(): file.addToSample(local_density_of_states, 'twoprobe_configuration', 'Local Density Of States')

local_density_of_states_1 = calculateLocalDensityOfStates(
    self_consistent_calculation = scf,
    energy = 0.0*electronVolt,
    quantum_number = ((0.0,0.0),Spin.Down),
    green_function_infinitesimal = 1.0e-5*electronVolt
)
if processIsMaster(): file.addToSample(local_density_of_states_1, 'twoprobe_configuration', 'Local Density Of States 1')


but i were been told that:NLValueError:One of or more atoms has a different number of orbitals.
how can i do ,if i want to calculate the LDOS of fermi energy?
what dose the quantum_number in "quantum_number = ((0.0,0.0),Spin.Down)"mean? dose it mean at a certain k point ,a certain energy such as fermi energy,the density_of_states of spin down state?or it means a series of k points?