Messages

46

General Questions and Answers / Re: How to calculate the surace energy of TiO2 with different facets, e.g. (001),(0)

« on: April 1, 2016, 09:44 »

Also, be careful with the oscillations in the surface energy you will observe as a function of the number of layers.
Here a detailed methodology is described for vicinal tio2 surfaces http://dx.doi.org/10.1063/1.4840515

47

General Questions and Answers / Re: LOCPOT 1D projector bug

« on: March 10, 2016, 16:07 »

Thanks for reporting the issue, we are aware of it and we will fix it as soon as possible.
This is only present for non-polarized calculations.
We'll keep you posted as soon as this is fixed.

48

General Questions and Answers / Re: problem about optimizing lattice constant in the new ATK2015

« on: February 24, 2016, 14:59 »

That is a very very old piece of code. It won't work in ATK 2015.
An updated example for optimizing MoS2 monolayer is described here: http://docs.quantumwise.com/tutorials/vibrational_modes.html

49

General Questions and Answers / Re: NEB path

« on: January 30, 2016, 11:49 »

can  you check the individual log files neb_image.0, neb_image.1, ....
It can be that one of the parallel taks failed, perhaps because of a license issue.

50

General Questions and Answers / Re: Shape a graphen nanoribbon like a trapezoid

« on: January 27, 2016, 09:29 »

Here are some useful links on how to shape your structure to whatever form you wish:
http://docs.quantumwise.com/tutorials/vnl_3d_view.html
http://docs.quantumwise.com/tutorials/exploring_graphene.html
http://quantumwise.com/documents/tutorials/latest/GrapheneDevice/index.html/chap.conductance.html#chap.conductance.sect1.z-a-z20

51

General Questions and Answers / Re: Server could not re-checkout feature because:Software expired

« on: January 22, 2016, 10:23 »

About the license, it seems that your license server stopped running.
please port output of

lmxendutil -licstat

52

General Questions and Answers / Re: Effective mass analyzer

« on: January 4, 2016, 12:32 »

The Custom Analyzer plugins have been dismissed in VNL/ATK 2015 since the corresponding analysis are now well integrated build in analysis objects.
here is described how to use the new effective mass analysis http://quantumwise.com/publications/tutorials/item/500-effective-mass-of-electrons-in-silicon
Unfortunately, it does not show the fitting curve.

53

General Questions and Answers / Re: Question about calculating Work function of metal

« on: December 23, 2015, 08:49 »

plot the WF against vacuum spacer anche check for convergence, for example.
in ATK (LCAO method) 10 Å should be enough.

It is also a good idea to plot the effective potential along the direction perpendicular to your surfaces.
See here for more details: http://quantumwise.com/publications/tutorials/item/519-tuning-the-work-function-of-silver-by-deposition-of-ultrathin-oxide-layers

54

General Questions and Answers / Re: transmission-spectrum output differences running on cluster using VNL-ATK2015

« on: December 15, 2015, 16:02 »

You used a different basis set.
You should use the Cerda.graphite and Hoffmann for Carbon and Hydrogen respectively:

Code

basis_set = [
    HoffmannHuckelParameters.Hydrogen_Basis,
    CerdaHuckelParameters.Carbon_graphite_Basis,
    ]

55

General Questions and Answers / Re: Calculate Workfunction from LOCPOT

« on: December 15, 2015, 10:51 »

Hi Dominique,
can you provide the LOCPOT and OUTCAR files which gives you the 2.2 eV work function with VNL?
if they are confidential you can send an email to support@quantumwise.com.
thanks!
Umberto

56

General Questions and Answers / Re: Size of the Dense Matrices

« on: December 14, 2015, 13:35 »

There are several tutorials that describe the dynamical matrix and how the number of displacements is defined.
http://quantumwise.com/publications/tutorials/itemlist/category/94-phonons-and-thermal-properties

57

General Questions and Answers / Re: The calculation did not converge to the requested tolerance!

« on: December 14, 2015, 13:32 »

your structure is indeed quite different from this last picture.
You have to rotate by 90 degrees around the x axes your molecule.

out of curiosity, can you add the full reference of that paper?

58

General Questions and Answers / Re: electron-phonon interaction in two probe system

« on: December 14, 2015, 13:27 »

can you please provide input/output files?

Also note that 2015.1 has been released: http://quantumwise.com/products/download

59

General Questions and Answers / Re: How to simulate FET's metal-semiconductor contact's Schottky barrier

« on: December 14, 2015, 10:48 »

For both questions the answer is to test your set up according to your assumptions.
Here is a relevant tutorial: http://quantumwise.com/documents/tutorials/latest/InAsDevice/index.html/

60

General Questions and Answers / Re: NiGe PDOS

« on: December 14, 2015, 10:46 »

Please attach your full input script for more detailed comments.
1)  yes and no. complete and good basis set should give similar results. did you optimized  the structure in both cases?
for Ge I would compare lower states, which are not reported in your reference. As you can see these states are very low and quite "noisy" around the Fermi level.
2) not sure if it wise it for sure fine to do that.
3) 3d.