[Pw_forum] DFT+U and non-collinear calculations

[Pietro Bonfa']

Dear Dr. Smogunov,

following your suggestion I tried with various versions of pw.x. Results:

5.0   :   working
5.0.2 :   working
5.0.99:   not working
5.1rc1:   not working

So this looks like a bug in the 5.1rc1 version. I'll try to figure out
why this happens with the help of diffs files.

Thanks for your help,
kind regards,
Pietro Bonfa'


On 04/30/2014 11:00 AM, Alex Smogunov wrote:
> Dear Pietro.
> I have tried your input with QE 5.0, it works fine for me, try it.
> The problem could also arrise from diagonalization method though it is
> strange...
> Try to set diagonalization = 'cg'.
> good luck,
> Alexander
> 
> 
> 
> 2014-04-29 17:18 GMT+02:00 Pietro Bonfa' <pietro.bonfa at fis.unipr.it
> <mailto:pietro.bonfa at fis.unipr.it>>:
> 
>     Dear Dr. Alexander Smogunov,
> 
>     the short digression on the non-linear core corrections was intended to
>     explain why I need DFT+U to correctly reproduce the insulating and
>     magnetic ground state of La2CuO4.
> 
>     I attached a modified version of example 11 (that I called example12).
>     I set all the parameters to zero just to check if everything is working
>     properly. I tried also with realistic values for U and J but I obtained
>     the same errors.
> 
>     Thanks,
>     kind regards,
>     Pietro Bonfa'
> 
> 
> 
>     On 04/29/2014 04:13 PM, Alex Smogunov wrote:
>     > Dear Pietro.
>     > It should work, in principle, at least for US PPs ... even though
>     > I do not understand what is the relation between  non-linear core
>     > corrections and
>     > the need for DFT+U together with spin-orbit, moreover you set up
>     all the
>     > parameters
>     > essentially to zero. Anyway the code should run even in this case.
>     Could
>     > you provide the complete
>     > input file, please?
>     > regards,
>     > Alexander
>     >
>     >
>     >
>     > 2014-04-28 10:52 GMT+02:00 Pietro Bonfa'
>     <pietro.bonfa at fis.unipr.it <mailto:pietro.bonfa at fis.unipr.it>
>     > <mailto:pietro.bonfa at fis.unipr.it
>     <mailto:pietro.bonfa at fis.unipr.it>>>:
>     >
>     >     Dear All,
>     >
>     >     I would like to compare the total energies of various
>     non-collinear
>     >     magnetic configurations in La2CuO4 (LCO).
>     >
>     >     I started working with pseudopotentials from the PSLibrary,
>     the GBRV
>     >     library and some home brewed norm conserving Cu pseudos. After
>     a short
>     >     analysis I realized that the experimentally observed
>     insulating and
>     >     antiferromagnetic ground state is obtained only if I remove
>     non-linear
>     >     core corrections. This holds true for both my NC pseudos and
>     the Cu
>     >     pseudo from PSL 1.0.0 (I didn't try GBRV).
>     >
>     >     Nonetheless, since studying the magnetic ground state of LCO
>     without
>     >     using non-linear core corrections does not make much sense to
>     me, I
>     >     tried DFT+U with noncolin and lspinorb flags set to true.
>     >
>     >     More precisely, I added the following lines to example 11 in the
>     >     QE-5.1rc1 release
>     >
>     >         lda_plus_u=.true.
>     >         lda_plus_u_kind=1
>     >         Hubbard_U(1)=1.d-10
>     >         Hubbard_J(1,1)=1.d-10
>     >         Hubbard_J(2,1)=0.0
>     >
>     >     Depending on the pseudopotential type (PAW, US or NC) I get
>     errors like:
>     >
>     >          from cdiaghg : error #        19
>     >          eigenvectors failed to converge
>     >     or
>     >          from cdiaghg : error #       109
>     >          S matrix not positive definite
>     >
>     >     So my question is: is lda+u and non-collinear magnetism still not
>     >     implemented, is this a bug or me doing something utterly wrong?
>     >
>     >     Thanks,
>     >     kind regards,
>     >     Pietro Bonfa'
>     >
>     >     --
>     >     Pietro Bonfa' - PhD student
>     >     Dipartimento di Fisica e Scienze della Terra "Macedonio Melloni"
>     >     Viale delle Scienze 7A
>     >     43124 Parma - Italy
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> 
>     --
>     Pietro Bonfa' - PhD student
>     Dipartimento di Fisica e Scienze della Terra "Macedonio Melloni"
>     Viale delle Scienze 7A
>     43124 Parma - Italy
> 
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-- 
Pietro Bonfa' - PhD student
Dipartimento di Fisica e Scienze della Terra "Macedonio Melloni"
Viale delle Scienze 7A
43124 Parma - Italy