[Pw_forum] Praseodymium Pseudopotential(s)
Vo, Trinh (388C)
Trinh.Vo at jpl.nasa.gov
Mon Aug 30 00:16:26 CEST 2010
Since I have the same interest of generating a PP for an rare-earth element
(Yb), if you don't mind, could you send me the input that you used to
generate PP for Ce. I am trying to generate a PP for Yb, using QE, but I
have failed so far. I would like to look at the input file generating Ce PP
to have an idea, since they are of the same Lanthanide family.
Thank you very much,
On 8/26/10 6:11 PM, "w2agz" <w2agz at pacbell.net> wrote:
> Hi Stefano(s),
> Thanks for your feedback. I wouldn't be surprised that praseodymium would
> have similar issues as cerium. Ce is [Xe]4f 5d 6s2 and Pr [Xe]4f3 6s2,
> and, as I mentioned below, Pr-1237 is the only lanthanide copper oxide
> perovskite that doesn't superconduct. (The Ce copper oxides don't form in
> the same perovskite structure).
> In any event, your comment that correlations in these materials are very
> cogent, and that employing a LDA+U framework is mandatory.
> You mentioned "...posting pseudos on the web"...is it possible for QE users
> to submit PPs they've found handy to the QE Wiki? I constructed a PP
> favoring the Cu 3d9 4s2 configuration which I found very useful for
> calculating ground state antiferromagnetic properties of CuO, both as
> tenorite and tetragonal rocksalt. I generated it using the QE PP code, and
> could make it available (no guarantees, of course!).
> From: "Stefano de Gironcoli" <degironc at sissa.it>
> Sent: Thursday, August 26, 2010 12:21 AM
> To: "PWSCF Forum" <pw_forum at pwscf.org>
> Cc: "Stefano Fabris" <fabris at democritos.it>
> Subject: Re: [Pw_forum] Praseodymium Pseudopotential(s)
>> Dear Paul,
>> I have no experience with Praseodymium but have been involved in some
>> calculations with Cerium that shares with it the mixed valence nature.
>> Stefano Fabris (here in cc) generated a couple of pseudopotentials
>> that were successfully used in a number of studies. He can send you
>> more info... and possibly post the pseudos on the web...
>> Beware however that in order to obtain even qualitatively sensible
>> results with Ce (and I guess also with Pr) DFT+U or a similarly
>> self-interaction corrected scheme is mandatory.
>> best regards,
>> Stefano de Gironcoli
>> w2agz wrote:
>>> Ciao Tutti (especially Paolo, Mateo etc.),
>>> OK, I've been away for a while, busy with energy issues and trying to
>>> understand why Alex Mueller may have been on the right track wrt to
>>> explaining why high temperature superconductivity manifests in the copper
>>> oxide perovskites. PW_FORUM is not the right place to "advertize" one's
>>> publications, but I owe much to the QE community and its creators and
>>> contributors. Contact me if you're interested in further info.
>>> The reason for this posting is as follows:
>>> (1) I'd like to investigate via QE-DFT the "properties" of several Pr,
>>> alkaline earth-oxide perovskites, and thus need to have an appropiate Pr
>>> pseudopotential, one that would be compatible with the PP library of QE.
>>> (2) Browsing the QE, Vanderbilt, Opium, Haber and Martins sites
>>> (US-PS, NC-PS), I could find "none" that were pregenerated.
>>> (3) Therefore, I may be "on my own," and would appreciate advice:
>>> a. Is the community aware of any suitable Pr PPs I could obtain and
>>> b. If not, I'd appreciate advice on how to generate my own, using
>>> either the "famous" ld1.x, or a suitable equivalent
>>> c. Does anyone know about or use the "Octopus" site
>>> (4) Pr is a particular pernicious element ([Xe] 4f3-6s2) . Simply
>>> put, it can be either 3+ or 4+.or somewhere in between - the 4f states
>>> are known to hybidize extensively. Studies I did at IBM on the Pr-1237
>>> system indicated its ground quantum state may be in some sort of "heavy
>>> fermion" configuration. Think about it. Why is not Pr-1237
>>> superconducting.or even metallic, even though its crystal structure is
>>> nearly identical to Y-1237? That's the most unsolved mystery of 20th
>>> century condensed matter physics.next to why the copper oxide perovskites
>>> are superconducting at all.
>>> Finally, I remind all of the wisdom of David Vanderbilt's remark,
>>> something to the effect, "Pseudopotential generation is a black art."
>>> Paolo, can you work your magic?
>>> Ciao, -Paul
>>> Pw_forum mailing list
>>> Pw_forum at pwscf.org
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