[Wien] Difference between "x lapw2 -qtl" and "x qtl"
Peter Blaha
peter.blaha at tuwien.ac.at
Wed Mar 15 08:51:37 CET 2023
Well, we can only guess something because there is not enough information.
Clearly: qtl has a limit of 25 atoms in case.inqtl
It should give you a corresponding error message, so you should be aware
of that.
On the other hand you said you limit the number of atoms to 2 in
case.inqtl, so this should not cause an error.
I would need the struct file together with an exact description of what
you have done and what does not work. Otherwise I cannot reproduce things.
PS: Why are you setting RLOs for all atoms ?? It does not make sense for
valence electrons of light atoms.
PPS: I'm also surprised that SO with (100) does not break more symmetry ???
Am 15.03.2023 um 01:32 schrieb pluto via Wien:
> Dear All,
>
> I am calculating one of the 1T TMDC materials. This material e.g. has a
> spin-polarized Dirac cone on the surface (see e.g. DOI
> 10.1088/2516-1075/ab09b7 for review of similar materials).
>
> I calculated 10L (15 inequivalent atoms) and 20L (30 inequivalent atoms)
> slabs. I allowed sgroup to find the space group (no. 164) in order to
> speed up the calculation. In this case it means each inequivalent atom
> has 2 equivalent positions.
>
> It is a spin polarized calculation with SOC. Band structures look good
> compared to the literature Wannier calculations.
>
> One obvious test is to check spin polarization of the Dirac cone.
>
> Band characters can be calculated either using
> x lapw2 -band -qtl -up/dn -so (default in w2web)
> or using
> x qtl -band -up/dn -so
>
> Importantly, in order to make x qtl work I need to
> cp case.in1 case.in1c
> although the system does have inversion (otherwise qtl gives an error
> and nothing is calculated). Is this allowed?
>
> Another problem is that for the 20L slab x spaghetti does not want to
> plot fat bands out of case.qtlup/dn produced by "x qtl". I didn't look
> at the case.qtlup/dn files in detail yet (I will, but it might take a
> while), but either they are incomplete (i.e. x qtl cannot handle a big
> slab), or spaghetti cannot handle these files beyond a certain size
> limit. On the other hand case.qtlup/dn produced by x lapw2 always work
> with fat bands. Of couse when using x qtl I limit the number of atoms in
> case.inq, and I typically only calculate characters for 2 outermost
> atoms (my case.inq pasted below). For 10L slab everything works fine.
>
> The plotted results (using w2web) for these two cases look very
> different. I tried plotting characters on couple of outermost atoms.
>
> x lapw2 does not show any spin polarization of the Dirac cone
> x qtl shows clear very high polarization of the Dirac cone
>
> This happens when I plot total character on a particular atom, is it not
> an effect related to some Y_lm character or things like that.
>
> I think in general I should split all atoms in order to get correct spin
> polarization (the so-called hidden spin polarization introduced by
> Zunger/Freeman). This is what one had to do with the 2H MoS2
> calculations several years back. But splitting all atoms would probably
> make 20L slab calculation prohibitive on my system (I think 20L would be
> unrealistic).
>
> But perhaps the QTL program can somehow do the job of splitting the
> equivalent atoms even on slab with equivalent positions.
>
> I also paste below case.inso, note that the direction of spin
> polarization quant. axis is along 100, i.e. in-plane, as it should for
> these materials.
>
> Best,
> Lukasz
>
>
> case.inq file:
>
> -9.0 3.0 Emin Emax
> 2 number of atoms
> 1 1 0 1 iatom,qsplit,symmetrize,locrot
> 3 0 1 2 nL, l-values
> 0 0 1
> 30 1 0 1 iatom,qsplit,symmetrize,locrot
> 3 0 1 2 nL, l-values
> 0 0 1
>
> case.inso
>
> WFFIL
> 4 0 0 llmax,ipr,kpot
> -10 1.9 Emin, Emax
> 1 0 0 h,k,l (direction of magnetization)
> 30 number of atoms with RLO
> 1 -3.53 0.0001 STOP atom-number, E-param for RLO
> 2 -3.53 0.0001 STOP atom-number, E-param for RLO
> 3 -3.53 0.0001 STOP atom-number, E-param for RLO
> 4 -3.53 0.0001 STOP atom-number, E-param for RLO
> 5 -3.53 0.0001 STOP atom-number, E-param for RLO
> 6 -3.53 0.0001 STOP atom-number, E-param for RLO
> 7 -3.53 0.0001 STOP atom-number, E-param for RLO
> 8 -3.53 0.0001 STOP atom-number, E-param for RLO
> 9 -3.53 0.0001 STOP atom-number, E-param for RLO
> 10 -3.53 0.0001 STOP atom-number, E-param for RLO
> 11 0.30 0.0000 CONT atom-number, E-param for RLO
> 12 0.30 0.0000 CONT atom-number, E-param for RLO
> 13 0.30 0.0000 CONT atom-number, E-param for RLO
> 14 0.30 0.0000 CONT atom-number, E-param for RLO
> 15 0.30 0.0000 CONT atom-number, E-param for RLO
> 16 0.30 0.0000 CONT atom-number, E-param for RLO
> 17 0.30 0.0000 CONT atom-number, E-param for RLO
> 18 0.30 0.0000 CONT atom-number, E-param for RLO
> 19 0.30 0.0000 CONT atom-number, E-param for RLO
> 20 0.30 0.0000 CONT atom-number, E-param for RLO
> 21 0.30 0.0000 CONT atom-number, E-param for RLO
> 22 0.30 0.0000 CONT atom-number, E-param for RLO
> 23 0.30 0.0000 CONT atom-number, E-param for RLO
> 24 0.30 0.0000 CONT atom-number, E-param for RLO
> 25 0.30 0.0000 CONT atom-number, E-param for RLO
> 26 0.30 0.0000 CONT atom-number, E-param for RLO
> 27 0.30 0.0000 CONT atom-number, E-param for RLO
> 28 0.30 0.0000 CONT atom-number, E-param for RLO
> 29 0.30 0.0000 CONT atom-number, E-param for RLO
> 30 0.30 0.0000 CONT atom-number, E-param for RLO
> 0 0 number of atoms without SO, atomnumbers
>
>
>
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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