If two consecutive points are "very" far away, the bands (?) code
assumes that you made a jump in the path and put them with the same path
coordinate. How far is "very" far is defined i na funny way: if thw new
step is twice as large as the previous one:
IF(dxmod >5*dxmod_save) THEN
!
! A big jumpin dxmod is a sign that the point xk(:,n) and xk(:,n-1)
! are quite distant and belong to two different lines. We put them on
! the same point in the graph
(bands.f90 line 564)
You can tweak the code, or tweak your path.
cheers
On 12/07/2022 12:09, Carl-Friedrich Schön wrote:
Dear all,
I have calculated the band structure for Si with 8 atoms in the UC
(conventional standard from MP) using QE6.4.
My input is:
/&control//
// calculation = 'bands'//
// prefix='Si_mp-149_conventional_standard'//
// tstress = .true.//
// tprnfor = .true.//
// pseudo_dir='/rwthfs/rz/cluster/home/cs825852/DFT/UPF_Ressources_NSCF/NC'//
// outdir='tmp'//
// disk_io='low'//
// wf_collect=.true.//
/// //
//&system//
// ibrav =0,//
// nat=8//
// ntyp=1//
// ecutwfc = 100//
// ecutrho = 400//
// occupations = 'fixed'//
// nbnd = 24//
/// //
//&electrons//
// mixing_beta = 0.2//
// conv_thr = 1.0d-10//
/// //
//ATOMIC_SPECIES//
//Si 28.086 Si.upf//
//ATOMIC_POSITIONS {crystal}//
//Si 0.25 0.75 0.25//
//Si -0.0 -0.0 0.5//
//Si 0.25 0.25 0.75//
//Si -0.0 0.5 0.0//
//Si 0.75 0.75 0.75//
//Si 0.5 0.0 0.0//
//Si 0.75 0.25 0.25//
//Si 0.5 0.5 0.5//
//CELL_PARAMETERS//
//10.334398 0.0 0.0//
//0.0 10.334398 0.0//
//0.0 0.0 10.334398//
//K_POINTS {crystal_b}//
//12//
//0.0 0.0 0.0 20.0//
//0.5 0.0 0.5 20.0//
//0.5 0.25 0.75 20.0//
//0.375 0.375 0.75 20.0//
//0.0 0.0 0.0 20.0//
//0.5 0.5 0.5 20.0//
//0.625 0.25 0.625 20.0//
//0.5 0.25 0.75 20.0//
//0.5 0.5 0.5 20.0//
//0.375 0.375 0.75 20.0//
//0.625 0.25 0.625 20.0//
//0.5 0.0 0.5 20.0/
My bands.x output however states:
/high-symmetry point: 0.0000 0.0000 0.0000 x coordinate 0.0000//
// high-symmetry point: 0.5000 0.0000 0.5000 x coordinate
0.7071//
// high-symmetry point: 0.5000 0.2500 0.7500 x coordinate
1.0607//
// high-symmetry point: 0.3750 0.3750 0.7500 x coordinate
1.2374//
// high-symmetry point: 0.0000 0.0000 0.0000 x coordinate
1.2374//
// high-symmetry point: 0.5000 0.5000 0.5000 x coordinate
2.1035//
// high-symmetry point: 0.6250 0.2500 0.6250 x coordinate
2.4096//
// high-symmetry point: 0.5000 0.2500 0.7500 x coordinate
2.5864//
// high-symmetry point: 0.5000 0.5000 0.5000 x coordinate
2.9400//
// high-symmetry point: 0.3750 0.3750 0.7500 x coordinate
3.2462//
// high-symmetry point: 0.6250 0.2500 0.6250 x coordinate
3.5524//
// high-symmetry point: 0.5000 0.0000 0.5000 x coordinate 3.8585/
As you can see, the fourth and fifth KPoint have the same x
coordinate, while they are not identical.
The .gnu output seems to state the correct energies, while the
x-coordinate just stays identical for this range:
/ 1.2198 -4.4150//
// 1.2286 -4.4160//
// 1.2374 -4.4163//
// 1.2374 -4.4466//
// 1.2374 -4.4594//
// 1.2374 -4.4544//
// 1.2374 -4.4316//
// 1.2374 -4.3909/
/..../
I had the same issue occur with Cu (mp-30).
While I have found some outputs with the same problem (?) online, it
was the topic of the discussion.
Is this a bug, or am I missing/misunderstanding some intended behavior?
Thanks and best,
Carl-Friedrich Schön, PhD Student, RWTH Aachen
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--
Dr. Lorenzo Paulatto
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/
23-24/423 B115, 4 place Jussieu 75252 Paris CX 05
_______________________________________________
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)
users mailing list users@lists.quantum-espresso.org
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