You can use either, but you won't get much benefit from noncolin=.true. if you don't use full relativistic pseudos. Also, noncolinear calculations are more expensive, and some features are not implemented in this case. On 4 Mar 2016 3:32 a.m., "Mingchao Wang" <[email protected]> wrote:
> Dear Dr. Clavijo, > > Thank you for your helpful information. My concern is about the setting of > noncolin variable. My question is: If I use scalar-relativistic > pseudopotentials for all atoms of CH3NH3PbI3, should I use noncolin=.TRUE > or noncolin=.FALSE? Now I am not quite whether scalar-relativistic > pseudopotentials directly include the nonlinear calculation. > > Regards, > > MC Wang > > On Thu, Mar 3, 2016 at 8:42 PM, Josue Itsman Clavijo Penagos < > [email protected]> wrote: > >> Dear Mingchao Wang, as far as i know, the best case is to use >> Pseudopotentials of the same kind for all atoms, and preferably >> full-relativistic, so the spin-orbit coupling can be accurately taken into >> account, since it its known that Eg calculated without relativistic >> spin-orbit coupling is , although not very different that the >> no-relativistic calculated one due to cancelling over- and under- >> estimation issues in non-relativistic pseudopotentials, not a good obtained >> one. Long words short: you're getting a Eg value from a not so much >> physically accurate calculation framework. >> >> On the other hand, you not need to use H atoms to calculate Band >> Structure, since their contribution is only in the deep levels of valence >> and conduction bands (not near the band gap), unless you are into studying >> deep band structure actually. >> >> Finalliy, I think that noncolin=true is a must for spin-orbit >> calculations in pw.x , but i'm not 100% sure if that's true for an hybrid >> inorganic-organic system such as a CH3NH3PbI3 unit cell crystal at any >> temperature and crystal system of those this material can form. >> >> Anyway, Would you mind to put your pw input file, so i can compare my >> calculations with yours, since i'm currently working on the same system? >> that would be very very helpful to me and for others fellows in the forum >> and all would help you more and better, also. >> >> Best regards, >> >> Josué Clavijo, PhD. >> Assistant Professor >> Universidad Nacional de Colombia >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum > > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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