[QE-users] High-symmetry path in bands.x differs from K_POINTS input

[wenusaras]

Dear Vishad,

Thank you very much for your quick reply.
Could you please provide a bit more detail on what you meant by “One is 
crystal, the other is cartesian”?
Let me restate my situation for clarity.

In my band-structure input (pw.scf.bands.in, calculation = 'bands') for 
a 2-D material with ibrav = 8, I specify the k-path in crystal 
coordinates:

K_POINTS crystal_b
5
0.00  0.00  0.00 10 !G
0.50  0.00  0.00 10 !X
0.50  0.50  0.00 10 !C
0.00  0.50  0.00 10 !Y
0.00  0.00  0.00 10 !G

After running this SCF/bands calculation and then bands.x with
&bands
    prefix  = 'A'
    filband = 'B.dat'
    lsym = .false.
/

the bands.x output lists:
     high-symmetry point:  0.0000 0.0000 0.0000   x coordinate   0.0000 
--> G
     high-symmetry point:  0.5000 0.0000 0.0000   x coordinate   0.5000 
--> X
     high-symmetry point:  0.5000 1.7459 0.0000   x coordinate   2.2459 
--> Not C
     high-symmetry point:  0.0000 1.7459 0.0000   x coordinate   2.7459 
--> Not Y
     high-symmetry point:  0.0000 0.0000 0.0000   x coordinate   4.4918 
--> G

I was expecting the same crystal coordinates as in the input, but 
bands.x reports larger y-values such as 1.7459.(attached bands.x output)
Could you please advise me on how to get the output high-symmetry points 
to match the crystal coordinates I set in the input (pw.scf.bands.in)?

(I also notice that for simpler cells (e.g. ibrav = 1) the reported 
points match the input fractions—perhaps the cell vectors)

Thank you again for your help.
Wenusara Satheekshana


______________________________________________________________________________________________________________________________________
On 2025-09-28 17:33, Vahid Askarpour wrote:
> One is crystal, the other is cartesian.
> 
> Cheers,
> Vahid
> 
> Vahid Askarpour
> Department of Physics and Atmospheric Science
> Dalhousie University
> Halifax, Canada
> 
>> On Sep 28, 2025, at 8:49 AM, wenusaras <wenusaras at uom.lk> wrote:
>> 
>> CAUTION: The Sender of this email is not from within Dalhousie.
>> 
>> Dear QE users,
>> 
>> I am new to Quantum ESPRESSO and working on a 2D material (ibrav = 8)
>> using QE v7.2.
>> For a band-structure calculation I provided the following path in the
>> pw.scf bands input:
>> 
>> K_POINTS crystal_b
>> 5
>> 0.00  0.00  0.00 10
>> 0.50  0.00  0.00 10
>> 0.50  0.50  0.00 10
>> 0.00  0.50  0.00 10
>> 0.00  0.00  0.00 10
>> 
>> The SCF run completed, and I then executed bands.x.
>> However, the bands.x output lists different high-symmetry points:
>> 
>>   Reading collected, re-writing distributed wavefunctions
>>     high-symmetry point:  0.0000 0.0000 0.0000   x coordinate   0.0000
>>     high-symmetry point:  0.5000 0.0000 0.0000   x coordinate   0.5000
>>     high-symmetry point:  0.5000 1.7459 0.0000   x coordinate   2.2459
>>     high-symmetry point:  0.0000 1.7459 0.0000   x coordinate   2.7459
>>     high-symmetry point:  0.0000 0.0000 0.0000   x coordinate   4.4918
>> 
>> My goal is to obtain the band structure along exactly the k-path
>> specified in the input file, but the output shows different 
>> coordinates
>> (e.g., 1.7459 instead of 0.5).
>> 
>> Could someone clarify why bands.x is changing the path and how I can
>> ensure the high symmetry points match with the input?
>> 
>> Thank You in advance
>> Wenusara Satheekshana
>> _______________________________________________________________________________
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> 
> _______________________________________________________________________________
> The Quantum ESPRESSO Foundation stands in solidarity with all
> civilians worldwide who are victims of terrorism, military aggression,
> and indiscriminate warfare.
> --------------------------------------------------------------------------------
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users

-- 
Thank You
Wenusara Satheekshana
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