Modified Ta PAW potential to calculate accurate EFGs
Posted: Tue May 09, 2023 11:23 am
Dear VASP community,
I am Ian Yap Chang Jie, a PhD student from the Civil Engineering department of the University of Duisburg Essen and in collaboration with different theoretical and experimental groups. I work in nuclear spectroscopy (Time differential perturbed angular correlation or TDPAC) measuring electric field gradients (See wiki/index.php/Electric_Field_Gradient). In particular, I am working on rutile TiO2 with Tantalum (Ta)-induced substitutional defects. In addition to our experimental work, we have been using CP-PAW, developed by Peter Blöchl, to calculate EFGs of the material. However, we are currently considering switching to VASP, because it offers the HSE06 exchange functional in addition to the PAW method.
As EFG calculations require high-quality PAW sets, we must include the semi-core electrons of titanium and tantalum. We already had a look at the list of available PAW potentials under wiki/index.php/Available_PAW_potentials and found that for Ti, we could use the Ti_Sv potential, which has 12 valence electrons corresponding to 3s2 3p6 3d2 4s2 configuration. However, for Ta, we could only find the Ta_pv potential, which has a valency of 11, which I believe corresponds to 5p6 5d3 6s2. In our studies using CP-PAW, we found that the 5s2 and 4f14 states must be included in the valence states to generate an accurate EFG, which replicates our experimental Vzz values. So, we would need to increase the total number of valence electrons to 26-27 (depending on the charge of the supercell that we have generated).
Hence, I would like to ask if there exists a Ta PAW potential that we could use for this purpose? And if so, how do we activate it?
Thank you for considering my question, and I hope to hear from your soon.
Best Regards,
Ian Yap Chang Jie
I am Ian Yap Chang Jie, a PhD student from the Civil Engineering department of the University of Duisburg Essen and in collaboration with different theoretical and experimental groups. I work in nuclear spectroscopy (Time differential perturbed angular correlation or TDPAC) measuring electric field gradients (See wiki/index.php/Electric_Field_Gradient). In particular, I am working on rutile TiO2 with Tantalum (Ta)-induced substitutional defects. In addition to our experimental work, we have been using CP-PAW, developed by Peter Blöchl, to calculate EFGs of the material. However, we are currently considering switching to VASP, because it offers the HSE06 exchange functional in addition to the PAW method.
As EFG calculations require high-quality PAW sets, we must include the semi-core electrons of titanium and tantalum. We already had a look at the list of available PAW potentials under wiki/index.php/Available_PAW_potentials and found that for Ti, we could use the Ti_Sv potential, which has 12 valence electrons corresponding to 3s2 3p6 3d2 4s2 configuration. However, for Ta, we could only find the Ta_pv potential, which has a valency of 11, which I believe corresponds to 5p6 5d3 6s2. In our studies using CP-PAW, we found that the 5s2 and 4f14 states must be included in the valence states to generate an accurate EFG, which replicates our experimental Vzz values. So, we would need to increase the total number of valence electrons to 26-27 (depending on the charge of the supercell that we have generated).
Hence, I would like to ask if there exists a Ta PAW potential that we could use for this purpose? And if so, how do we activate it?
Thank you for considering my question, and I hope to hear from your soon.
Best Regards,
Ian Yap Chang Jie