Sorry to jump in this argument. I may be not of much help.
For the question of overlapping bands or strange mixing of bands...In my
experience, bands become easier to be plotted if when you run bands.x
you add in the input file the flag: no_overlap= .true.
That flag avoid eigenvalues overlapping and even plotband.x does a nice job.
Francesco
University of Strathclyde
On 18/04/16 08:56, Giovanni Cantele wrote:
bands crossing are spurious and they are due to the fact that, after
running bands.x (or in the case you have not used it at all), the
bands order might be incorrect. That means that the n-th band (that
is, the band that at each k-point is
plotted as n-th eigenvalue) might actually contain, at different
k-points, energies belonging to different bands. In this case, if you
not only plot the points but also connect them with lines, you might
see spurious connection lines between
different bands. The way to cure this problem is to run bands.x before
plotband.x, but with a sufficient number of k-points (if they are too
distant bands.x might fail in following a band, that is, in assigning
a given eigenvalue to a band).
Giovanni
On 18 Apr 2016, at 05:34, Manu Hegde <[email protected]
<mailto:[email protected]>> wrote:
Hi Giovanni,
Thanks for your advice.
I have calculated band structure for the zinc blende GaP lattice.
When I plotted using gnuplot it looks okay (plotgnu_gap.ps
<http://plotgnu_gap.ps/>). But .ps format from the plotband.x
(plotband_gap.ps <http://plotband_gap.ps/>) does not look properly
and there some bands crossing. I am not sure why it is happening like
this. I have attached both the files.
Regards,
Manu
Dr.Manu Hegde
Postdoctoral Fellow
Department of Chemistry
University of Waterloo
Waterloo, ON, N2L 3G1
On Wed, Apr 6, 2016 at 6:26 AM, Giovanni Cantele
<[email protected] <mailto:[email protected]>>
wrote:
Quite likely, you did not calculate the band structure along a
path in the Brillouin zone, but used the output of the scf
calculation (k-point grid). After running pw.x with
calculation=‘scf’ or calculation=‘relax’,
you need to rerun it with a new input file, calculation=‘bands’
and K_POINTS card containing a suitable path of k-points. See
also examples of band structure calculation included in the
QE-package.
You can set Emin (Emax) to the value of the lowest (highest)
eigenvalue), unless you need to select some specific energy range.
Giovanni
PS Users of this forum are usually kindly requested to sign
messages with affiliation
On 06 Apr 2016, at 05:25, Manu Hegde <[email protected]
<mailto:[email protected]>> wrote:
Hello All,
I was trying to plot band structure of PbTiO3, I could only see
dots in bands.ps <http://bands.ps/> file. I am not sure what is
the reason for this. Is it due to the wrong k-point selection?.
I am also not sure about energy selection along y-axis (Emax,
Emin). I have attached bands.ps <http://bands.ps/> file please
have a look. Please help to overcome from this problem.
Thanks and Regards
Manu
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CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: [email protected]
<mailto:[email protected]>
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Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: [email protected] <mailto:[email protected]>
Phone: +39 081 676910
Skype contact: giocan74
ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: http://people.na.infn.it/~cantele
<http://people.na.infn.it/%7Ecantele>
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