Re: [Wien] proper k-points for Nd

[Lyudmila Dobysheva]

25.01.2019 3:32, Tribhuwan Pandey wrote:

*Nd RMT: 2.44* RKmax: 9.33,

18.01.2019 0:19, Victor Zenou wrote:
> I used RMT=2.7 a.u. RMT*Kmax=8.5

Besides difference in Rkmax, there is a difference in Rmt between 
Pandey's and Victor's calculation. Could this large Rmt be the main reason?


Best wishes
Lyudmila Dobysheva
--
Physics-Techn.Institute,
Udmurt Federal Research Center, Ural Br. of Rus.Ac.Sci.
426000 Izhevsk Kirov str. 132
Russia
---
Tel. +7 (34I2)43-24-59 (office), +7 (9I2)OI9-795O (home)
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Re: [Wien] Metal or semimetal

[delamora]

If Ef is near the edge of a band, close to the bandgap then it would be a bad 
conductor, since the bands would be quite flat (and the velocity of the 
electrons is proportional to the slope of the band) and the DOS would be low, 
so I would call it a semimetal




Dear wien2k users:

I have a question that does not have any relation with wien2k but I would be 
grateful if you can answer me or send me a document:

When the fermi level passes slightly below the top of the valance band with the 
presence of a wide gap, this indicates a metal or semimetalic behavior.?

Thank you in advance
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Re: [Wien] proper k-points for Nd

[Tribhuwan Pandey]

Dear Victor, and Wien2k developers,

I recently ran some calculations on bulk Nd, and I thought of adding some
points to this discussion. There are few differences between mine and
Victor's calculations: I am using *wien2k-14.1 (built with intel compiler
and fftw), APW basis*, *Nd RMT: 2.44, RKmax: 9.33, and GMax = 12.0*

I first ran the calculations with -cc 0.0001, once calculations was
converged  to eliminate the possibility of false convergence, I cranked it
up to 0.1.

Below it the convergence with respect to K points:

K-points in the full  Energy (RyD)
   Bz
MMTOT
 300-77040.4784888916.54268
1200-77040.4780601716.75716

6000-77040.47815237 16.79681
12000  -77040.4781539716.80318
24000  -77040.4781510316.80044
3   -77040.4781500716.80171
36000   -77040.4781495216.80263


In my calculations energy convergences reasonably well (0.01 meV)  with
respect to  K-points.

PS. Victor, I am sharing my files at this link

https://drive.google.com/file/d/1rOKoRph6zVAkgAUjc64-Xgi6av3XmdSU/view?usp=sharing

if it helps to track down the issue. Not sure if your problem occurs from
the different wien versions, which is quite unlikely.

Hope it helps.

Thanks
Pandey

-- 


Tribhuwan Pandey, Ph. D
Postdoctoral Research Associate
Condensed Matter Theory Group
Materials Science and Technology Division
Oak Ridge National Laboratory, Oak Ridge, USA
_
_
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Re: [Wien] proper k-points for Nd

[Laurence Marks]

Did you reduce the RMTs? Until you do I expect GIGO.

On Thu, Jan 24, 2019 at 2:28 PM Victor Zenou  wrote:

> Dear all Wien2k users
>
> Finally I used HDLOs for f and d electrons, lvns=6, TEMPS 0.002 as
> L.Marks mentioned. RMT*Kmax=8.5 as before.
>
>
> case.in1:
>
> WFFIL EF= 0.5 (WFFIL, WFPRI, ENFIL, SUPWF)
>
> 8.50 10 6 ELPA pxq hm (R-MT*K-MAX,MAX L IN WF,V-NMT,lib,gridshape,hm/lm)
>
> 0.30 6 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
>
> 0 0.30 0. CONT 1
>
> 0 -2.95 0.0001 STOP 1
>
> 1 0.30 0. CONT 1
>
> 1 -1.48 0.0010 CONT 1
>
> 3 0.30 0.0010 CONT 2
>
> 2 0.30 0.0010 CONT 2
>
> 0.30 6 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
>
> 0 0.30 0. CONT 1
>
> 0 -2.95 0.0001 STOP 1
>
> 1 0.30 0. CONT 1
>
> 1 -1.48 0.0010 CONT 1
>
> 3 0.30 0.0010 CONT 2
>
> 2 0.30 0.0010 CONT 2
>
> K-VECTORS FROM UNIT:4 -9.0 1.5 117 emin / de (emax=Ef+de) / nband
>
>
> case.in
> 
> 2:
>
> TOT (TOT,FOR,QTL,EFG,FERMI)
>
> -12.0 56.0 0.50 0.05 1 EMIN, NE, ESEPERMIN, ESEPER0, iqtlsave
>
> TEMPS 0.002 (GAUSS,ROOT,TEMP,TETRA,ALL eval)
>
> 0 0 2 0 4 0 4 3 6 0 6 3 6 6
>
> 0 0 2 0 3 3 4 0 5 3 6 0 6 6
>
> 12.00 GMAX
>
> NOFILE FILE/NOFILE write recprlist
>
>
>
> I’ve started from stracth and used 1000 k-points (81 IBZ).
>
> I didn’t use -it etc.
>
> ec 0.0001 and cc 0.0001.
>
> It converged rather fast after 1.5 hr after running 170 cycles.
>
>
> But I got *WARNING** TOTAL ENERGY IN Ry = -77040.36606788
>
> Looking at case.scf I saw:
>
> :WARN : QTL-B value eq. 4.32 in Band of energy 0.57054 ATOM= 1 L= 3
>
> :WARN : You should change the E-parameter for this atom and L-value in
> case.in1
>
>
> So I have to change “E-parameter“ and “L-value” in case.in1. I can do
> trail and error, but if someone have hint on direction I would be happy to
> hear. Could it be other parameter?
>
> Victor
>
> ‫בתאריך יום א׳, 20 בינו׳ 2019 ב-20:01 מאת ‪Peter Blaha‬‏ <‪
> pbl...@theochem.tuwien.ac.at‬‏>:‬
>
>> I disagree with Lauries point: Eventually I want to do even an
>> "unphysical" calculation, of course it might be you have to pay a price
>> for it, because this unphysical model as eg. a spike in the DOS at EF.
>> And mixer should lead to convergence, but sometimes has problems
>> (Lauries mixer is still one of the big advantages of WIEN2k. I know
>> other codes, which would not be able to converge a 5f system at all).
>>
>> In any case, put a HDLO (5f) and increase LVNS=6 first.
>>
>> Most importantly: why are you starting from scratch when doing the
>> k-mesh tests. This is very error prone and in particular burns cpu-hours
>> completely unnecessarily.
>>
>> One of my main "advises" is always: do an init_lapw only ONCE ! (except
>> you have to change spheres).
>>
>> You will get much better internal convergence when you continue using
>> the previous calculation:
>>
>> loop:
>> runsp 
>> save XXX-k-points
>> x kgen (increase the mesh always at least by a factor of 2 (maybe even 4).
>> goto loop
>>
>> I'm not so much surprised about the k-mesh for a magnetic 5d-element
>> calculation. I start with 1 k-points for every metallic spd-element
>> and test it with 5 k. You may need 100 000 or even more. (optics for
>> fcc Al is not fully converged with 1 000 000 k-points !). It does not
>> cost much cpu, since you should start with a nearly converged calculation.
>>
>> Your :DIS is still quite large, try to bring it below 0.0001
>>
>> You can try TEMPS 0.002 as Laurence advised. This will most likely
>> improve convergence, but most likely also reduce MMT a little bit, which
>> is ok when you compare with room temp experiments, but not for 4k
>> measurements ...
>>
>>
>>
>> Am 20.01.2019 um 17:50 schrieb Laurence Marks:
>> > Sorry Fabien, I am dubious that k-points is the issue, I suspect a bad
>> > model.
>> >
>> > Let me explain, repeating some things I have said before or are in the
>> > mixer notes albeit perhaps buried.
>> >
>> > An "easy" assumption that many people make is that dft problems are
>> well
>> > posed, so have "simple" fixed-point solutions. In fact this is not
>> true.
>> > In reality dft problems have stacks of numerical issues which leads to
>> > "noise". You can think about this in terms of finding the minimum of
>> > "F(x) = x*x + Constant*Noise(x)" where Noise(x) is some randomly
>> > generated noise. The larger Constant is, the larger the deviation is
>> > from x=0 of the apparent minimum. Averaging over more k-points may
>> > reduce Constant, but often in my experience does relatively little.
>> >
>> > A symptom of noise is poor convergence -- which is clearly what is
>> > occurring here.
>> >
>> > If you improve the convergence rate you will reduce the noise. Some
>> > suggestions:
>> >
>> > 1) Use HDLO and red

Re: [Wien] proper k-points for Nd

[Victor Zenou]

Dear all Wien2k users

Finally I used HDLOs for f and d electrons, lvns=6, TEMPS 0.002 as L.Marks
mentioned. RMT*Kmax=8.5 as before.


case.in1:

WFFIL EF= 0.5 (WFFIL, WFPRI, ENFIL, SUPWF)

8.50 10 6 ELPA pxq hm (R-MT*K-MAX,MAX L IN WF,V-NMT,lib,gridshape,hm/lm)

0.30 6 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)

0 0.30 0. CONT 1

0 -2.95 0.0001 STOP 1

1 0.30 0. CONT 1

1 -1.48 0.0010 CONT 1

3 0.30 0.0010 CONT 2

2 0.30 0.0010 CONT 2

0.30 6 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)

0 0.30 0. CONT 1

0 -2.95 0.0001 STOP 1

1 0.30 0. CONT 1

1 -1.48 0.0010 CONT 1

3 0.30 0.0010 CONT 2

2 0.30 0.0010 CONT 2

K-VECTORS FROM UNIT:4 -9.0 1.5 117 emin / de (emax=Ef+de) / nband


case.in2:

TOT (TOT,FOR,QTL,EFG,FERMI)

-12.0 56.0 0.50 0.05 1 EMIN, NE, ESEPERMIN, ESEPER0, iqtlsave

TEMPS 0.002 (GAUSS,ROOT,TEMP,TETRA,ALL eval)

0 0 2 0 4 0 4 3 6 0 6 3 6 6

0 0 2 0 3 3 4 0 5 3 6 0 6 6

12.00 GMAX

NOFILE FILE/NOFILE write recprlist



I’ve started from stracth and used 1000 k-points (81 IBZ).

I didn’t use -it etc.

ec 0.0001 and cc 0.0001.

It converged rather fast after 1.5 hr after running 170 cycles.


But I got *WARNING** TOTAL ENERGY IN Ry = -77040.36606788

Looking at case.scf I saw:

:WARN : QTL-B value eq. 4.32 in Band of energy 0.57054 ATOM= 1 L= 3

:WARN : You should change the E-parameter for this atom and L-value in
case.in1


So I have to change “E-parameter“ and “L-value” in case.in1. I can do trail
and error, but if someone have hint on direction I would be happy to hear.
Could it be other parameter?

Victor

‫בתאריך יום א׳, 20 בינו׳ 2019 ב-20:01 מאת ‪Peter Blaha‬‏ <‪
pbl...@theochem.tuwien.ac.at‬‏>:‬

> I disagree with Lauries point: Eventually I want to do even an
> "unphysical" calculation, of course it might be you have to pay a price
> for it, because this unphysical model as eg. a spike in the DOS at EF.
> And mixer should lead to convergence, but sometimes has problems
> (Lauries mixer is still one of the big advantages of WIEN2k. I know
> other codes, which would not be able to converge a 5f system at all).
>
> In any case, put a HDLO (5f) and increase LVNS=6 first.
>
> Most importantly: why are you starting from scratch when doing the
> k-mesh tests. This is very error prone and in particular burns cpu-hours
> completely unnecessarily.
>
> One of my main "advises" is always: do an init_lapw only ONCE ! (except
> you have to change spheres).
>
> You will get much better internal convergence when you continue using
> the previous calculation:
>
> loop:
> runsp 
> save XXX-k-points
> x kgen (increase the mesh always at least by a factor of 2 (maybe even 4).
> goto loop
>
> I'm not so much surprised about the k-mesh for a magnetic 5d-element
> calculation. I start with 1 k-points for every metallic spd-element
> and test it with 5 k. You may need 100 000 or even more. (optics for
> fcc Al is not fully converged with 1 000 000 k-points !). It does not
> cost much cpu, since you should start with a nearly converged calculation.
>
> Your :DIS is still quite large, try to bring it below 0.0001
>
> You can try TEMPS 0.002 as Laurence advised. This will most likely
> improve convergence, but most likely also reduce MMT a little bit, which
> is ok when you compare with room temp experiments, but not for 4k
> measurements ...
>
>
>
> Am 20.01.2019 um 17:50 schrieb Laurence Marks:
> > Sorry Fabien, I am dubious that k-points is the issue, I suspect a bad
> > model.
> >
> > Let me explain, repeating some things I have said before or are in the
> > mixer notes albeit perhaps buried.
> >
> > An "easy" assumption that many people make is that dft problems are well
> > posed, so have "simple" fixed-point solutions. In fact this is not true.
> > In reality dft problems have stacks of numerical issues which leads to
> > "noise". You can think about this in terms of finding the minimum of
> > "F(x) = x*x + Constant*Noise(x)" where Noise(x) is some randomly
> > generated noise. The larger Constant is, the larger the deviation is
> > from x=0 of the apparent minimum. Averaging over more k-points may
> > reduce Constant, but often in my experience does relatively little.
> >
> > A symptom of noise is poor convergence -- which is clearly what is
> > occurring here.
> >
> > If you improve the convergence rate you will reduce the noise. Some
> > suggestions:
> >
> > 1) Use HDLO and reduce RMT
> > 2) Reduce RMT and use HDLO
> > 3) Larger LM (e.g. 8)
> > 4) Larger gmax in case.in2 (e.g. 16)
> > 5) Use TEMPS 0.0018 (room temperature)
> > 6) Peter's suggestions
> >
> > On Sun, Jan 20, 2019 at 10:27 AM t...@theochem.tuwien.ac.at
> >   > > wrote:
> >
> > Hi,
> >
> > If not too expensive, you could try more k-points (2 and 25000)
> > to see if the fluctuations persist.
> >
> > Questions: how many atoms in the unit cell? Are you optimizing the
> > position of ato

[Wien] Metal or semimetal

[Wien2k User]

Dear wien2k users:

I have a question that does not have any relation with wien2k but I would
be grateful if you can answer me or send me a document:

When the fermi level passes slightly below the top of the valance band with
the presence of a wide gap, this indicates a metal or semimetalic behavior.?

Thank you in advance
___
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