[Wien] Plane-wave cutoff in W2K

[Marcos Veríssimo Alves]

Hi all,

I have a doubt regarding PW cutoffs in W2K. In the paper

Charge localization or itineracy at LaAlO3∕SrTiO3 interfaces: Hole polarons,
oxygen vacancies, and mobile electrons
R. Pentcheva and W. E. Pickett
Phys. Rev. B 74, 035112 (2006)

The authors specify their convergence parameters in the following way:

"Inside the muffin tins wave functions are expanded in spherical harmonics up
to $l_{max}^{wf}=10$ and nonspherical contributions to the electron density
and potential up to $l_{max}^{pot}=6$ are used. The energy cutoff for the
planewave representation in the interstitial is $E_{max}^{wf}=19$ Ry for
the wave functions and $E_{max}^{pot}=196$ Ry for the potential."

I would like to specify my parameters in the same way. For $l_{max}^{wf}$
and $l_{max}^{pot}$, these parameters are found in case.in:

8.00       10    4 (R-MT*K-MAX; MAX L IN WF, V-NMT)

and the last two would give me $l_{max}^{wf}$ and $l_{max}^{pot}$. However,
I am in doubt on how to find the PW cutoff for the wavefunctions in the
interstitials and for the potential (or how to determine these cutoffs, if
they can't be readily found in the output files).

For the wavefunctions, it is somewhat straightforward: kmax^2 gives the
cutoff energy in Ry. I suppose I could just take the smallest cutoff (since
there will be different kmax for the different elements) as a specification,
or is the maximum/minimum value of kmax used for all elements, instead?

For the expansion of potentials in plane waves, I'd suppose the energy
cutoff would be simply gmax^2 (as specified in case.in2), but I'd like to
confirm it, even under the risk of having made a stupid question :)

Any help will be greatky appreciated.

Thanks in advance,

Marcos

---------------
Marcos Veríssimo Alves
Universidad de Cantabria, Spain
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