Messages

1

General Questions and Answers / How can I execute a serial of *.py files by one controlling script?

« on: December 22, 2009, 03:11 »

Dear sirs,

I have to run a serial of py files, if I run them one by one, it is very inconvenient. So how to compile a script that can control them to be executed one by one.

2

General Questions and Answers / Re: Two basic questions, I hope you can give me some advice

« on: November 19, 2009, 13:00 »

Today I have tried several temperatures for electrode eigenstate occupation parameters, e.g. 10K ,300K, 1000K and so on. But there is no dramatic effect. Later I changed exchange correlation type and subtituted GGA PBE for LDA PZ. The result is unideal yet. In partical, atoms wire is unstable, so it may be very difficult to find an equilibrium state under bias. Is there any other way that I can utilize in ATK to calculate I-V curve for 1D copper atoms wire?

3

General Questions and Answers / Re: Two basic questions, I hope you can give me some advice

« on: November 18, 2009, 13:52 »

Thanks very much for your attention! But that is not the point to the problem.
Before the calculation I got the lattcie constant from SCF calculation of 1D copper atoms wire. The lattice constant represents the lowest energy.
In order to make the calculation convergence, I have tried several ways:
1) Decrease the k points of Brillouin Zone;
2) Simplify the basis set that I select;
3) Reduce convergence criterion;
4) Increase calcualtion steps;
5) Decrease central region atoms from 15 to 3 gradually.
But they seemed no effect, the calculation still can not converge.
The electrodes of my calculation is also 1D copper atoms wire. Whether should I enlarge my electrodes to help the system to converge?

4

General Questions and Answers / Re: Why can not I bulid a supercell like this?

« on: November 18, 2009, 08:59 »

It does work. Thank you very much!

5

General Questions and Answers / Why can not I bulid a supercell like this?

« on: November 18, 2009, 03:52 »

# Loop over lattice constants
import numpy
for a in numpy.arange(2.0,2.8,0.01):
# Define the unit cell
super_cell = [[ 12.   ,   0.   ,   0.   ],
             [  0.   ,  12.   ,   0.   ],
             [  0.   ,   0.   ,  11.075+2*a]]*Angstrom
# Define elements
elements = [Copper,    Copper,    Copper,    Aluminium,
            Copper,    Copper,    Copper]
# Define coordinates
coordinates = [[  0.        ,   0.        ,   0.        ],
               [  0.        ,   0.        ,   2.215     ],
               [  0.        ,   0.        ,   4.43      ],
               [  0.        ,   0.        ,   4.43+1*a  ],
               [  0.        ,   0.        ,   4.43+2*a  ],
               [  0.        ,   0.        ,   6.645+2*a ],
               [  0.        ,   0.        ,   8.86+2*a  ]]*Angstrom
# Set up the periodic atom configuration
periodic_atom_configuration = PeriodicAtomConfiguration(
    super_cell,
    elements,
    cartesian_coordinates=coordinates
    )

When I run the program, it shows 'expected an indented block'. What does this mean?

6

General Questions and Answers / Re: Two basic questions, I hope you can give me some advice

« on: November 17, 2009, 14:18 »

I have solved the second problem. By controlling the argument in index_list, I could get all the transmission eigenchannels.

7

General Questions and Answers / Re: Two basic questions, I hope you can give me some advice

« on: November 17, 2009, 11:16 »

Thanks very much for your attention. These two attechment files are the input files for calculating I-V curve of copper wire, I hope you can give me some advice. For the second problems I have calculated transmission eigenchannels ,but I do not know how to display them in Nanoscope module respectively in VNL. In other words, in the example of aluminium wire it only display one transmission eigenchannel, I want to know how to display the other transmission eigenchannel.

8

General Questions and Answers / Two basic questions, I hope you can give me some advice

« on: November 17, 2009, 02:49 »

1).I wanted to calculate the current versus bias curve of 1D copper wire, so I constructed two electrodes respectively, which consisted of 6 copper atoms in a line. The central region consisted of a chain of 15 copper atoms. The problem was that when the bias was applied, the calculation did not converge. I want to know why the system does not converge and what parameters should I control if I want to get the I-V curve of copper wire?
2).I have calculated three transmission eigenvectors of  copper wire and I want to study the transimission eigenchannels of the wire, how can I display the transmission eigenchannels in VNL?