Hi,
I had a look inside lapwso package and except a small redundancy in
rlomain.F, see lines 84 to 89,
code snip
bk(1)=bkrot(1)*br1(1,1)+bkrot(2)*br1(1,2)+bkrot(3)*br1(1,3)
bk(2)=bkrot(1)*br1(2,1)+bkrot(2)*br1(2,2)+bkrot(3)*br1(2,3)
bk(3)=bkrot(1)*br1(3,1)+bkrot(2)*br1(3,2)+bkrot(3)*br1(3,3)
BK(1)=BKROT(1)*BR1(1,1)+BKROT(2)*BR1(1,2)+BKROT(3)*BR1(1,3)
BK(2)=BKROT(1)*BR1(2,1)+BKROT(2)*BR1(2,2)+BKROT(3)*BR1(2,3)
BK(3)=BKROT(1)*BR1(3,1)+BKROT(2)*BR1(3,2)+BKROT(3)*BR1(3,3)
/code snip
I have not found nothing that would solve my problem.
However, the non continuous behavior occurs once MBJ is turned on, see
attached plot of spin-orbit split valence band in wurtzite GaAs from
Gamma (k=zero) towards K point (shifted for a comparative purpose).
Just a note, that increasing IFFT do not heal the non-smooth behavior.
Any suggestions? Thanks in advance,
Martin
On Wed, Dec 3, 2014 at 12:04 PM, Martin Gmitra martin.gmi...@gmail.com wrote:
Dear Peter,
Thank you for your effort. I have modified lapwso and lapw1 so that
1/3 and 2/3 are entered in machine precision. The non-continuous
behavior stays the same even with your suggestions for RKmax=10,
Emax=.9 and adding RLOs in case.inso (could you comment please why
consider RLOs in the GaAs case?). I had also changed the non-primitive
translations exactly to 0 (did not mentioned last time) with no
effect.
I am observing that splitting goes perfectly smooth along the Gamma-H
line. Therefore I plotted splitting along Gamma-K direction with a
tiny kz component. Please see attached plots (idv=36000) for kz=0;
kz=1/36000 and kz=5/36000. The smoothness gets slowly recovered. Could
it be a helpful information to extract a reason for the problem?
Best regards,
Martin
On Tue, Dec 2, 2014 at 12:03 PM, Peter Blaha
pbl...@theochem.tuwien.ac.at wrote:
Hi,
I could confirm the problem, but unfortunately I cannot offer a solution.
These irregulations do not go away with increasing RKMAX or Emax (best is
anyway to set EMAX=.9 in case.in1 for such a study).
Changing compiler options (higher precision of ifort) or even changing to
gfortran or older WIEN2k versions does not cure the problem.
They come from eigenvalue differences in the 9th digit after the comma.
If I check internal accuracy, for instance by calculations for all 6
equivalent k-points (x,x,0;-x,-x,0;2x,-x,0,) such differences should
still be feasible, because internal consistency is 11 digits in lapwso (but
14 in lapw1, so clearly we are loosing something there), see below.
58 0.449061656042513
58 0.449061656068273
58 0.449061656046884
58 0.449061656046190
58 0.449061656032196
58 0.449061656067333
*
In any case, for an accurate value of your quantity (delta-E/k) you need at
least
RKMAX=10
Emax=.9 (all eigenvalues in lapw1)
add RLOs for both atoms in case.inso !!
and then have to extrapolate from the smooth part of the curve.
Change the non-primitive translation in case.struct to be exactly 0 !
PS: another sophisticated test would be to convert your structure to an
orthorhombic one and test if the problem comes from the hexagonal lattice
(positions like 1/3, ... are never correct in the input), although then
you might have a problem to specify your k-points with full accuracy; or at
least modify lapw1/lapwso and set the input 0.333 to 1/3 internally ..
On 12/02/2014 08:22 AM, Martin Gmitra wrote:
Dear Stefaan,
Yes, I have increased the Emax parameter to 18 Ry, see blue curve in
right plot. Indeed, it is one of the most important parameters.
Best,
Martin
On Mon, Dec 1, 2014 at 1:20 PM, Stefaan Cottenier
stefaan.cotten...@ugent.be wrote:
Thanks for your reply and suggestions. I went with RKmax up to 12Ry
and it turned out that 11 and 12 should be okay, since the splitting
starts to oscillate (change in the increasing trend with increased
RKmax). Concerning the non smooth behavior of the curve I did several
test calculations playing around with the input parameters and none of
the changes have brought desired healing of the step close to 0.003. I
am attaching plots to the attachment.
From your mail, it's not clear whether or not you tried to increase
Emax, as
Fabien suggested. This is specified in the last line of case.in1, and is
different from RKmax which is at the top of that file. For spin-orbit
effects, this is the most important precision-determining feature.
Stefaan
On Sun, Nov 30, 2014 at 12:02 AM, t...@theochem.tuwien.ac.at wrote:
Actually, the most important is maybe the number of bands calculated
by lapw1 which are used for the 2nd variational procedure for the
spin-orbit coupling. So, to increase Emax in case.in1 (up to 20 Ry or
even
more) should be tried.
F. Tran
On Sat, 29 Nov 2014,
