Topics

1

General Questions and Answers / The distribution of wave functions

« on: August 9, 2018, 15:16 »

Dear sir,
The Brock state of the band crossing the Fermi level in a nanoribbon at the gamma point is calculated. It is found that when the width of the nanoribbon  is reduced, this band still exists,  but although the distribution of wave functions of other atoms is the same, there is no wave function distributed over an edge atom and its nearest atoms.  So, can it be said that the orbitals of these atoms do not contribute to this band?  What could cause this phenomenon?  Is  it relate to the electron transfer? Are these two bands the same band? In ATK, what other analyses are helpful to explore the causes of this phenomenon? Thank you!

2

General Questions and Answers / Electrochemical potential and the deformation of the device under finite bias

« on: July 5, 2018, 11:27 »

Dear sir,
How is the spatial profile of the electrochemical potential along the device treated for the transport calculations? In ATK, which function can be calculated to display it?
Another question, in ATK, has the deformation of the device under finite bias been considered? How can I calculate it and display the deformation? Does this deformation have an important impact on electronic transport? 

3

General Questions and Answers / An error about voltage drop

« on: July 16, 2016, 14:23 »

Dear sir,
I am trying to calculate the voltage drop for Li-h2, following the tutorial given in link: http://www.quantumwise.com/documents/tutorials/latest/ATKTutorialDevice/index.html/chap.iv.html, I calculate the Transmission Spectrum and Electrostatic Difference Potential under 0V and 1V, but it always appears an index error: list index out of range (refers to voltage_drop = potential[1]-potential[0]). And then, I correct the .py as follows: firstly, I calculates the Transmission Spectrum and Electrostatic Difference Potential under 0V and saves in a.nc, then calculate them under 1V and saves in b.nc, finally I calculate the voltage drop using the following script:

Code

# Read the configurations
configuration_list_a = nlread('a.nc', DeviceConfiguration)
configuration_list_b = nlread('b.nc', DeviceConfiguration)

#calculate the electrostatic potentials
potential_0V = ElectrostaticDifferencePotential(configuration_list_a[0])
potential_1V = ElectrostaticDifferencePotential(configuration_list_b[0])

# Calculate the voltage drop.
voltage_drop = potential_1V-potential_0V

# Save the voltage drop to voltage_drop.nc
nlsave('voltage_drop.nc', voltage_drop, object_id='drop1V')

I get the same contour plot, but the colorbar is different, mine is in a range of -0.041-0.0015, what’s wrong with me?