Messages

1

General Questions and Answers / how can we determine polarization?

« on: April 5, 2011, 22:28 »

Hello,
I was checking the forum to find a way to determine the polarization of piezoelectric material but didnt find it, so is there anyone who knows how to do it.

Thanks

Raouf Mbarki

2

General Questions and Answers / Re: some basic questions about atk ( building supercell, optimizing lattice, ...)

« on: March 14, 2011, 02:21 »

Thanks Nordland for your help so you mean when i use optimizegeometry it uses your script?
Anders, try any pdf file in the section Tutorial and go to the bottom to the section Legacy tutorials for ATK/VNL 2008.10 like for example this link http://quantumwise.com/documents/tutorials/latest/ATK_TutorialSession_Part1_SCF.pdf it is giving me Page not found and all the other pdf also.

3

General Questions and Answers / Re: some basic questions about atk ( building supercell, optimizing lattice, ...)

« on: March 13, 2011, 18:27 »

Thanks Nordland, so if i have a good understanding, this means that the accuracy of the optimized lattice constant will depend on the selected calculator. I am testing GaAs material and some properties like dielectric and capacitance, do you have any suggestions of a suitable calculator or specific parameters to use here. It is bad that your script is outdated, you dont have any recent version?

Thanks for the clarifications
Raouf

4

General Questions and Answers / some basic questions about atk ( building supercell, optimizing lattice, ...)

« on: March 12, 2011, 21:43 »

Hello everybody
I ve just starterd using ATK and it is confusing me  . I am an MD guy and i know that we always need to relax the material and to get the optimized lattice constant, I have a couple of questions:
1- If i need to build my crystal, i know that i can go to database and select my material, but this gives me just a unit cell so how can i create a super cell?
2- Let's say that i want just to find the optimized lattice constant, do i still have to select a calculator in the script manager?
3- Whenever i try to find the optimized lattice constant, i select the material from the data base and then i select a DFT calculator and then i insert optimizegeometry but in the end i get the same initial lattice constant that i specified, am I missing something?
4- i searched in the forum how to relax the material and i found one script, but i didnt know how to use it or more specifically where to copy the script so that the software find it when i call it as a module.

One last comment, i think that it will be good to write a very basic tutorial that explain the main steps to do a simulation. Moreover some pdf files are missing in the website, (403 error page not found)

Any help will be valuable for me.
Thanks 

Raouf