Hello,
I agree with you that the procedure sometimes works, sometimes it does
not. I think the problem is that the wavefunctions at the points with
zero weight have no variational constraint, and depending of the linear
algebra used can converge to something sensible or not. One could try to
modify additional_kpoint.f90 and set some small but non zero weight to
the additional points (something in the 10^-6 to 10^-10 range). And then
renormalize the sum of the weights.
Can you try (and most importantly test) this yourself? I won't be able
to do any programming before a few weeks.
There are only a couple of line to change:
wk(nkstot_old+1:nkstot_old+nkstot_add) =0._dp
then, the other case :
wk(iq)=0.0d0
Instead of zero, you put a small constant. At the end, add something like
aux = SUM(wk)
CALL mp_sum(aux, intra_pool_sum)
wk = wk/aux
hth
On 29/07/2022 21:49, Антон Андреевич Гавриков wrote:
Dear colleagues,
we have tried to perfom band structure DFT-calculation of crystall
SrTiO3 with hybrid functionals.
When we run tests with silicon from the QE package it was OK.
But when we tried SrTiO3 following to the "fake" procedure in Si
example, we've got sharp peaks in band structure graph.
We have used PBE0 and HSE functionals with US pseudopotentials. The
result was the same.
Furthermore, despite we used nqx1 = 2 nqx2 = 2 nqx3 = 2 in scf-input,
in scf-output there is the record: EXX: q-point mesh: 1 1 1
Input-file:
&CONTROL
calculation = "scf"
restart_mode='from_scratch',
prefix = 'SrTiO3',
nstep = 900,
max_seconds = 8.64000e+04
pseudo_dir = "/home/QuantumEspresso/pseudo",
wf_collect = .true.
etot_conv_thr = 1.0d-8
verbosity ='high'
/
&SYSTEM
ibrav = 1,
a = 3.8931e+00,
nat=5,
ntyp=3,
occupations='smearing',
smearing ='gauss',
degauss = 0.005,
nspin= 1
ecutwfc = 55.0d0
ecutrho = 580.d0
input_dft = 'hse',
nqx1 = 2
nqx2 = 2
nqx3 = 2
/
&ELECTRONS
electron_maxstep = 800
conv_thr = 1.0d-8
mixing_beta = 0.3
/
&IONS
ion_dynamics ='bfgs'
/
&CELL
/
ATOMIC_SPECIES
O 15.9994 O.pbesol-n-rrkjus_psl.1.0.0.UPF
Sr 87.6200 Sr.pbesol-spn-rrkjus_psl.1.0.0.UPF
Ti 47.8670 Ti.pbesol-spn-rrkjus_psl.1.0.0.UPF
ATOMIC_POSITIONS {crystal}
O 0.5 0.0 0.5
O 0.5 0.5 0.0
O 0.0 0.5 0.5
Sr 0.0 0.0 0.0
Ti 0.5 0.5 0.5
K_POINTS automatic
8 8 8 0 0 0
ADDITIONAL_K_POINTS tpiba_b
8
0.0000000000 0.0000000000 0.0000000000 20 ! GAMMA
0.0000000000 0.5000000000 0.0000000000 20 ! X
0.5000000000 0.5000000000 0.0000000000 28 ! M
0.0000000000 0.0000000000 0.0000000000 36 ! GAMMA
0.5000000000 0.5000000000 0.5000000000 28 ! R
0.0000000000 0.5000000000 0.0000000000 0 ! X
0.5000000000 0.5000000000 0.0000000000 20 ! M
0.5000000000 0.5000000000 0.5000000000 0 ! R
Would you answer my question, is there a way to get appropriate band
structure picture with hybrid functional using the "fake" procedure?
Regards,
Gavrikov Anton,
PhD, researcher,
Saint-Petersburg State University.
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IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université
phone: +33 (0)1 442 79822 / skype: paulatz
http://www.impmc.upmc.fr/~paulatto/ - https://anharmonic.github.io/
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_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
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