Hello

You can multiply your primary cell size by integer number N in any direction you want and manualy add atoms (so that their cartesian positions will be also multiplayed by the same N number).

Abhinav, How do u generate input files for QE? Is there any GUI for it?

@saisud: look for PWgui program

Saisudkar you will find a folder PW in Quantum espresso folder ..there you will find lots of example. Try to get idea from there or study user manual , they have discussed there.

Or I can send some of my input files. Iam also new to quantum espresso but now I have learn it upto band structure. 

Thank you :) Yeah I could be able to generate input file using PWGUI. But I want to view the molecules. Is there any graphical user interface to see/draw the molecules as like Gauss view/IQMol for QE.

xcrysden is a good program to look at pwscf structures as it can read the input and output files directly, but you will have to edit the input file by text editor.

http://www.xcrysden.org/

Very late to the party, but if it's still relevant, you could have a go at the GUI in the ADF Modeling Suite, which has an interface for Quantum ESPRESSO, and easily builds supercells, slices surfaces etc.:

https://www.scm.com/support/downloads/gui-for-quantum-espresso/

I'm late to the party also, but there's a free GUI called BURAI. Very nice capabilities and easy to use. It's very easy to make supercells and then create vacancies or substitutions.

http://nisihara.wixsite.com/burai

It can be generated using material project and also using Xcrysden

If you have a pwscf file then proceed as follows:

1. Perform the Xcrysden command (xcrysden --pwi file.in)

2. On the main dialogue of Xcrysden, click "Display" and scroll down to "Unit of Repetition...) and click. Here, click on "Translational asymmetric unit".

3. On the main dialogue click "Modify" and then scroll down to "Number of Units Drawn" and click. Specify your cells in each direction and "OK". Here you drag the point to the corresponding number on each axis.

4. Click "File" on the main dialogue and click "Save XSF Structure". Give your file a name eg filename.xsf

5. Open the filename.xsf file (created in step 4 above). This file contains many other information, so scroll until you get to "ATOMS" which is your interest. Copy and paste in your file of the supercell.

NB

The atomic positions will show elements in their known mass numbers eg, 16 for S, 32 for Ge, edit as necessary. Remember to change "nat" to correspond to the new number of atoms. This process gives you atomic positions in angstrom. You need to find the corresponding cell parameters (just a multiple of number unit cell translations in each direction with the cell parameter of the unit cell).

Hope that helped someone.

Dear Abhinav Nag, If you need to create a supercell and are too lazy to create a small program to translate atoms, or to do it manually, you can use one of the following codes:

• XCrySDen (suggested by G. Mattioli)
• gaussview, or Avogadro (suggested by A. Shearer)
• use the VESTA program, it’s a beatiful and friendly program to see crystal structures and make supercell, this program save the atomic positions in XYZ format. Furthermore, runs on linux and win! (Arles V. Gil Rebaza)
• Utility “genlat.f” of DL_POLY (suggested by G. Lapenna)
• use the ‘spacegroup’ program in EXCITING package (http://exciting-code.org) to generate the supercell, use ‘fropho’ (http://fropho.sourceforge.net) to check the symmetry’ (Kun Yin, April 2009)
• use the PHON code: http://www.homepages.ucl.ac.uk/~ucfbdxa/ (Eyvaz Isaev, April 2009).

You can use the package ectract Esspresso data or postion or for if you not have i will Send you link

You can also obtain it through Aflow by inputting your obtained data from material project into a flow.

You can generate input files using PWgui which is a GUI(Graphical User Interface) for quantum calculations and to visualize structures, you can use xCrysden. you have option for viewing using xCrysden in PWgui itself or you can open xCrysden by typing in terminal and inserting the required input file. There are other ways but this is quite simple.

hello sir, I am trying to make graphene sheet by using PWgui and Xcrysden, but as in xcrysden I can choose the option of repetation of unit cells , it will give the structure of graphene but after this I didnt get how to run this in PWgui as i didnt get the option in PWgui for the repeatation of unit shell to make graphene sheet, please tell me.

Why Not using Vesta is quite simple to generate super cell