GULP - Input scripts - Clarification

Dear Prof.Gale,


I have the following questions.

Can I generate a supercell in VESTA and export it to GULP? GULP basically considers a spherical region and I am doubtful how this export will work.

Also, if in a structure, if I have to study doping, suppose say if I have replace 1 in 100 atoms by some other different atom then how can I do it ? Is it possible? Because I am thinking of how one can maintain electroneutrality in such case.

It will be helpful for me if you could clarify these.

Thanks in advance.

GULP uses a cell (or supercell) just the same as VESTA. GULP can also generate it’s own supercells. The only place there is a spherical region is in the Mott-Littleton method, but you still input a cell as the starting point as normal.

If you have a non-charge neutral defect then you can either use the Mott-Littleton method (which avoids explicit charge compensation) or you can use a supercell (in which case you need to compensate the charge or work with a charged unit cell, which has restrictions and requires case). This is all routine stuff that’s in the literature for many decades & so your supervisor should be able to explain it to you.