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<p>Dear all, <br>
</p>
<p>I have calculated the band structure for Si with 8 atoms in the
UC (conventional standard from MP) using QE6.4.</p>
<p>My input is:</p>
<p><i>&control</i><i><br>
</i><i> calculation = 'bands'</i><i><br>
</i><i> prefix='Si_mp-149_conventional_standard'</i><i><br>
</i><i> tstress = .true.</i><i><br>
</i><i> tprnfor = .true.</i><i><br>
</i><i> pseudo_dir='/rwthfs/rz/cluster/home/cs825852/DFT/UPF_Ressources_NSCF/NC'</i><i><br>
</i><i> outdir='tmp'</i><i><br>
</i><i> disk_io='low'</i><i><br>
</i><i> wf_collect=.true.</i><i><br>
</i><i>/ </i><i><br>
</i><i>&system</i><i><br>
</i><i> ibrav =0,</i><i><br>
</i><i> nat=8</i><i><br>
</i><i> ntyp=1</i><i><br>
</i><i> ecutwfc = 100</i><i><br>
</i><i> ecutrho = 400</i><i><br>
</i><i> occupations = 'fixed'</i><i><br>
</i><i> nbnd = 24</i><i><br>
</i><i>/ </i><i><br>
</i><i>&electrons</i><i><br>
</i><i> mixing_beta = 0.2</i><i><br>
</i><i> conv_thr = 1.0d-10</i><i><br>
</i><i>/ </i><i><br>
</i><i>ATOMIC_SPECIES</i><i><br>
</i><i>Si 28.086 Si.upf</i><i><br>
</i><i>ATOMIC_POSITIONS {crystal}</i><i><br>
</i><i>Si 0.25 0.75 0.25</i><i><br>
</i><i>Si -0.0 -0.0 0.5</i><i><br>
</i><i>Si 0.25 0.25 0.75</i><i><br>
</i><i>Si -0.0 0.5 0.0</i><i><br>
</i><i>Si 0.75 0.75 0.75</i><i><br>
</i><i>Si 0.5 0.0 0.0</i><i><br>
</i><i>Si 0.75 0.25 0.25</i><i><br>
</i><i>Si 0.5 0.5 0.5</i><i><br>
</i><i>CELL_PARAMETERS</i><i><br>
</i><i>10.334398 0.0 0.0</i><i><br>
</i><i>0.0 10.334398 0.0</i><i><br>
</i><i>0.0 0.0 10.334398</i><i><br>
</i><i>K_POINTS {crystal_b}</i><i><br>
</i><i>12</i><i><br>
</i><i>0.0 0.0 0.0 20.0</i><i><br>
</i><i>0.5 0.0 0.5 20.0</i><i><br>
</i><i>0.5 0.25 0.75 20.0</i><i><br>
</i><i>0.375 0.375 0.75 20.0</i><i><br>
</i><i>0.0 0.0 0.0 20.0</i><i><br>
</i><i>0.5 0.5 0.5 20.0</i><i><br>
</i><i>0.625 0.25 0.625 20.0</i><i><br>
</i><i>0.5 0.25 0.75 20.0</i><i><br>
</i><i>0.5 0.5 0.5 20.0</i><i><br>
</i><i>0.375 0.375 0.75 20.0</i><i><br>
</i><i>0.625 0.25 0.625 20.0</i><i><br>
</i><i>0.5 0.0 0.5 20.0</i></p>
<p>My bands.x output however states:<br>
<i></i></p>
<p> <i>high-symmetry point: 0.0000 0.0000 0.0000 x
coordinate 0.0000</i><i><br>
</i><i> high-symmetry point: 0.5000 0.0000 0.5000 x
coordinate 0.7071</i><i><br>
</i><i> high-symmetry point: 0.5000 0.2500 0.7500 x
coordinate 1.0607</i><i><br>
</i><i> high-symmetry point: 0.3750 0.3750 0.7500 x
coordinate 1.2374</i><i><br>
</i><i> high-symmetry point: 0.0000 0.0000 0.0000 x
coordinate 1.2374</i><i><br>
</i><i> high-symmetry point: 0.5000 0.5000 0.5000 x
coordinate 2.1035</i><i><br>
</i><i> high-symmetry point: 0.6250 0.2500 0.6250 x
coordinate 2.4096</i><i><br>
</i><i> high-symmetry point: 0.5000 0.2500 0.7500 x
coordinate 2.5864</i><i><br>
</i><i> high-symmetry point: 0.5000 0.5000 0.5000 x
coordinate 2.9400</i><i><br>
</i><i> high-symmetry point: 0.3750 0.3750 0.7500 x
coordinate 3.2462</i><i><br>
</i><i> high-symmetry point: 0.6250 0.2500 0.6250 x
coordinate 3.5524</i><i><br>
</i><i> high-symmetry point: 0.5000 0.0000 0.5000 x
coordinate 3.8585</i></p>
<p>As you can see, the fourth and fifth KPoint have the same x
coordinate, while they are not identical. <br>
</p>
<p>The .gnu output seems to state the correct energies, while the
x-coordinate just stays identical for this range:</p>
<p><i> 1.2198 -4.4150</i><i><br>
</i><i> 1.2286 -4.4160</i><i><br>
</i><i> 1.2374 -4.4163</i><i><br>
</i><i> 1.2374 -4.4466</i><i><br>
</i><i> 1.2374 -4.4594</i><i><br>
</i><i> 1.2374 -4.4544</i><i><br>
</i><i> 1.2374 -4.4316</i><i><br>
</i><i> 1.2374 -4.3909</i></p>
<p><i>....</i></p>
<p>I had the same issue occur with Cu (mp-30). <br>
</p>
<p>While I have found some outputs with the same problem (?) online,
it was the topic of the discussion. <br>
</p>
<p>Is this a bug, or am I missing/misunderstanding some intended
behavior?</p>
<p>Thanks and best, <br>
</p>
<p>Carl-Friedrich Schön, PhD Student, RWTH Aachen<br>
</p>
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