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Messages - ams_nanolab

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31
Use the effective mass analyzer in the bottom rt corner of the bandstructure analysis window.

32
General Questions and Answers / Re: Edit nc files
« on: February 13, 2017, 21:03 »
Okay. Good to know.

33
General Questions and Answers / Re: Edit nc files
« on: February 13, 2017, 15:52 »
Will ATK 2017 have backward compatability? I mean also read .nc files? Please do keep it.

34
General Questions and Answers / Re: Bandstructure export data
« on: February 13, 2017, 15:19 »
Okay that's good  :) Also is it possible to plot in 3D (like the Graphene mexican hat) image attached.

35
General Questions and Answers / Re: Edit nc files
« on: February 13, 2017, 15:14 »
No need. I did it . Just read and write the configuration files with the needed gIDs.  ;D It was trivial now that I think of it.  ;) :)

36
General Questions and Answers / Edit nc files
« on: February 13, 2017, 13:34 »
I have a .nc file with a lot of objects in it. Many of which I do not need anymore. To stop bloating the file size and to keep only relevant gIDs what should be done?

Is there any way to selectively remove/delete certain objects from a .nc file?


37
General Questions and Answers / Re: Bandstructure export data
« on: February 13, 2017, 13:31 »
I just want the E-k plot data and nothing else.

from the link I could not pick out the variables I need. kindly help.

I am getting:

# Band 0
x           Energy / eV  Fractional k-point
0.0000e+00  -1.7795e+01   [0.0000e+00, 0.0000e+00, 0.0000e+00]
2.0000e-02  -1.7794e+01   [0.0000e+00, 0.0000e+00, 1.0000e-02]
4.0000e-02  -1.7791e+01   [0.0000e+00, 0.0000e+00, 2.0000e-02]
6.0000e-02  -1.7785e+01   [0.0000e+00, 0.0000e+00, 3.0000e-02]

But I need

x           Energy / eV 
0.0000e+00  -1.7795e+01 
2.0000e-02  -1.7794e+01   
4.0000e-02  -1.7791e+01 
6.0000e-02  -1.7785e+01   

I could of course do post-processing, but a script helps in saving data directly into the format wanted.

38
General Questions and Answers / Bandstructure export data
« on: February 13, 2017, 12:10 »
In the ATK 2016.3 , the export bandstructure has lot more data including the k-point co-ordinates which is very good, but I want to export a more simple two column data (like earlier versions of ATK did) to a .dat file from the bandstructure object.

Could you help me with a python script for that?

39
Quote
If your question was related to using classical potentials with to relax your configuration, then it can actually make sense to run a pre-relaxation with classical potentials, but, to be in the safe side, I would at least run a DFT force calculation before calculating any properties with DFT, to check if the residual DFT-forces are sufficiently small.

exactly. 

40
General Questions and Answers / Re: Eff mass fitting plots
« on: February 13, 2017, 11:52 »
Okay, thats good. But how about Z-G-Z It's the same direction but would include both sides of the parabola? Does it affect accuracy or is it the same?

41
General Questions and Answers / Eff mass fitting plots
« on: February 11, 2017, 10:26 »
Hi,

To get the effective mass fitting plots in ATK 2016.3 I am trying the Local Bandstructure as in
http://docs.quantumwise.com/tutorials/inas_2d_mgga/inas_2d_mgga.html

But how to fit the top of the band in a symmetric way (i mean the two arms of the parabola/ fitting curve)?

What I see is just half of the parabola. This is true for points intermediate between G and Z also.

42
General Questions and Answers / Re: T(E) or Ge(E)
« on: February 11, 2017, 10:20 »
Okay, my bad. So it is indeed the T(E).

43
General Questions and Answers / T(E) or Ge(E)
« on: February 10, 2017, 21:13 »
In the manual

http://docs.quantumwise.com/manuals/Types/TransmissionSpectrum/TransmissionSpectrum.html
mentions A fully transmitting channel contributes 1 per spin. If you sum the spin channels, the total transmission of an ideal system is 2. Often, it is the energy dependent conductance which is reported in articles

Ge(E)=(e^2/h)T(E)

If total transmission of an ideal system is 2, what does quantumwise actually plot for the transmission spectra T(e) or Ge(E) ?

Because in many cases the value of transmission is well in excess of 2.

44
General Questions and Answers / Green's function method T(E)
« on: February 10, 2017, 20:44 »
Hi,
I was wondering when we calculate the transmission spectra of a material is it with the "non-equilibrium" Green's function method? Beacuse at zero bias the system is still in equilibrium.

Should it be just

"equilibrium transmission was evaluated with  Green's function method" or

"transmission was calculated with DFT"

Because T(E) seems a fundamental quantity which helps in calculating current etc. by Landauer method.

45
Don't think you will get the same level of accuracy with MD optimization as with DFT. Unless it's a Really GOOD classical potential which fits very well with DFT. So it's material and as a consequence parameter dependent.

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