Calculating Formation Energy
Posted: Mon Jun 22, 2009 1:07 pm
Hello dear Vasp users;
I want to calculate formation energy of defects -for now- without corrections. i hope to get a qualitative calculation; because the band gap and super-cell corrections seemed as a next step to me.
Here what I've understood about the process:
1. After optimizing the geometry of neutral host and getting total energy of the supercell,
2. then the defect is added to the structure and re-optimization is done.
3. If the defect causes a net charge, NELECT flag is used to get charged super-cell, we get a new total energy from this calculation.
4. The defect atom is put in a large cell (or an elemental lattice) to get its energy
Formation energy is 3-1+4 ?
What should we add to this calculation?
How can we calculate the chemical potentials of defects ?
Thank you for advance
<span class='smallblacktext'>[ Edited ]</span>
I want to calculate formation energy of defects -for now- without corrections. i hope to get a qualitative calculation; because the band gap and super-cell corrections seemed as a next step to me.
Here what I've understood about the process:
1. After optimizing the geometry of neutral host and getting total energy of the supercell,
2. then the defect is added to the structure and re-optimization is done.
3. If the defect causes a net charge, NELECT flag is used to get charged super-cell, we get a new total energy from this calculation.
4. The defect atom is put in a large cell (or an elemental lattice) to get its energy
Formation energy is 3-1+4 ?
What should we add to this calculation?
How can we calculate the chemical potentials of defects ?
Thank you for advance
<span class='smallblacktext'>[ Edited ]</span>