Messages

1

General Questions and Answers / How to calculate current value from the finite-bias transmission spectrum

« on: May 19, 2019, 07:55 »

Hi,

I am using the ATK 17 and I have gotten some finite-bias transmission spectrums.  Actually, I need to get the current value at a certain bias.  How can I get the current value from the hdf5 file( for example:ivcurve_selfconsistent_configuration_-0.05000V.hdf5)

I just forgot to use IV Curve to calculate the current. What should I do now?

BTW, I have low-spin state and high-spin state configuration. For high-spin state, I need spin-up  and spin-down current. For low-spin state, I need one current value. 

Thanks so much!

2

General Questions and Answers / Re: SCF can't be converged in IV curve calculation

« on: December 17, 2018, 11:09 »

Okay, thanks! I will try this later. And I am confused about another problem. For example, at 0.3V,  it is converged. But at 0.1V, it does not be converged. I wonder why the SCF can be converged at a larger bias, rather than a smaller one? I mean it may be like this trend: 0.1V(success), 02V(success), 0.3V(success), and 0.4V(fail). Now, I have this: 0.1V(fail), 02V(success), 0.3V(success), and 0.4V(fail)

3

General Questions and Answers / SCF can't be converged in IV curve calculation

« on: December 17, 2018, 10:00 »

Hi,

  How to solve the convergence problem when doing IV calculation?  SCF cannot be converged at 0.4  and 0.5V. (0.3V is okay) I have read the https://docs.quantumwise.com/technicalnotes/negf_convergence_guide/negf_convergence_guide.html#negf-convergence-guide-pulay
carefully. First,   I increase the parameter Maximum steps to 250. (fail). Since I find dE and dH became oscillated. Then I  just decrease the Damping factor to 0.01 and increase the number of History steps to 35. (still fail) I also try to increase the k-sampling factor a bit. (fail as well)
  What am I supposed to do now?

Thank you so much!

4

General Questions and Answers / Re: How to calculate the change in the electrostatic energy

« on: December 9, 2018, 04:59 »

Hi,

  I've followed your guidance to compute the dE. I am faced with a new problem now. I have attached all files, including the error, and py files. Could you help me?
  Thank you so much!!!!

5

General Questions and Answers / Re: How to calculate the change in the electrostatic energy

« on: December 8, 2018, 01:42 »

Hi,

  If I have computed the dE, then is that mean I could get the energy jump at the interface, as shown in the picture?
  Thank you!

6

General Questions and Answers / How to calculate the change in the electrostatic energy

« on: December 7, 2018, 09:21 »

Hi,
 
  I wonder how to calculate the change in the electrostatic energy. I've already done a script to calculate the electrostatic potential of the device, but an error occurred "The parameter 'configuration' must be an instance of one of the following: BulkConfiguration, MoleculeConfiguration".
  My goal is to draw a picture like the following picture.
  Can you help me solve this problem?

7

General Questions and Answers / Re: How to calcaule the excess electrons in the center magnetic atom?

« on: December 4, 2018, 02:17 »

Thank you! I've solved this problem.

8

General Questions and Answers / How to calcaule the excess electrons in the center magnetic atom?

« on: December 3, 2018, 07:03 »

Hi,
 
  Here is my problem. How can I calculate the excess electrons in the center magnetic Fe atom (N_Fe)and in 3d orbitals of the Fe atom(N_3d)?

  By the way, I've got the total magnetic moment  by following the script:
# -------------------------------------------------------------
# Mulliken population
# -------------------------------------------------------------
mulliken_population = MullikenPopulation(bulk_configuration)
nlsave('magnetic_hs.nc', mulliken_population)
nlprint(mulliken_population)

# Majority and minority populations
popUp = mulliken_population.atoms(Spin.Up)
popDown = mulliken_population.atoms(Spin.Down)

# Magnetic moments
moments = popUp - popDown

print "Individual magnetic moments"
for i in range(len(moments)):
    print  i , moments

# Calculate total magnetic moment / unit cell.
mag_mom =  (popUp.sum() -  popDown.sum())

print
print "Total magnetic moment / unit cell"
print mag_mom

9

General Questions and Answers / Re: SCF can't be converged when calculating zero-bias transmission in MTJ device

« on: December 3, 2018, 06:51 »

Thank you so much!

10

General Questions and Answers / SCF can't be converged when calculating zero-bias transmission in MTJ device

« on: November 15, 2018, 13:10 »

Hi,
  Here is my problem. The  SCF can't be converged when calculating zero-bias transmission in MTJ device by using ATK 17. However, SCF is finished when using ATK 13.
  Could you tell me how to solve this problem? I want to do the calculation with ATK 17. The file is attached.

Thank you so much！

11

General Questions and Answers / Re: TMR calculation

« on: November 6, 2018, 05:08 »

For i in range(0,201):
    transmission_para = nlread('mgo_para.nc', TransmissionSpectrum)[ i ]

I got err "index out of range". How can I do to deal with TransmissionSpectrum with energy (-1,1,201)