[Pw_forum] complex band of Cu(111)

[Manoj Srivastava]

Dear Alaxendar and Letizia Chiodo,
Thank you very much for your reply. 
Did you use my input file for this calculation, or you have your own input
file, in that case would you mind sending me your input file? The thing is
I am using 3 atoms hexagonal unit cell for the Cu bulk. I guess the
problem in my input file is about the direction in which i am trying to
calculate the bands. In the last few lines of 'inputcond'
 	1
	0 0 1
	100 
 I assume that the second line is the direction, and last line dictates
how fine my k points are in that direction. Does the second line always
have to be always in Kx or Ky or Kz direction. Can't I use any combination
of Kx and Ky or Kz?  In my calculation to make sure that I was trying to
sample the right K points in BZ, I used example 1, given in the PWSCF
manual, as reference where they calculate real bands structure of Cu with
1 atom fcc unit cell. Then, I transformed the most symmetric directions
i.e. delta, sigma and lambda lines, used in BZ of example 1 to the BZ of
hexagonal lattice. But unfortunately I did not get the real part of
complex bands to match up with the one in example1! Also, in this
direction, I did not get any imaginary part of K !  I appreciate your help
in this matter. Also, would you mind sending references on comples bands,
if you know any,specially on which the code summary_band.f90 is based.

Regards,
Manoj


 
On Wed, 25 Jun 2008, Alexander wrote:

> Dear Manoj
> On my PC with espresso-4.0 I do get one band around the Fermi energy
> as it should be. My output for energies around Ef looks like this:
> ------------------------------
>         k(    1) = (  -1.0000000   1.7320000), wk =   1.0000000
> 
>  ngper, shell number =           39          24
>  ngper, n2d =           39          39
>  Nchannels of the left tip =            1
>         k1(2pi/a)    k2(2pi/a)       E-Ef (eV)
> 
>    0.0891385   0.0000000   0.4000000
>  Nchannels of the left tip =            1
>         k1(2pi/a)    k2(2pi/a)       E-Ef (eV)
> 
>    0.0568822   0.0000000   0.2000000
>  Nchannels of the left tip =            1
>         k1(2pi/a)    k2(2pi/a)       E-Ef (eV)
> 
>    0.0228076   0.0000000   0.0000000
>  Nchannels of the left tip =            1
>         k1(2pi/a)    k2(2pi/a)       E-Ef (eV)
> 
>   -0.0133793   0.0000000  -0.2000000
>  Nchannels of the left tip =            1
>         k1(2pi/a)    k2(2pi/a)       E-Ef (eV)
> 
>   -0.0520218   0.0000000  -0.4000000
> ------------------------------------------------------
> The problem is however that though the code calculates
> correctly all the complex bands, the subroutine (summary_band.f90)
> writing the bands in the file 'bands.cu' and in the common
> output file confuses two branches at k_z and -k_z in the present
> case where no mirror symmetry in the XY plane is present so that k_z
> is not equivalent to -k_z. I will fix this problem in the CVS version
> as soon as possible. Thank you for reporting the problem.
> Best regards,
> Alexander Smogunov
> 
> On Monday 23 June 2008 22:19, Manoj Srivastava wrote:
> > Dear PWSCF users,
> >  I am a new user of PWSCF and I have encountered a problem in calculating
> > complex band of Cu(111). I see a band gap and there are no bands crossing
> > Fermi energy. which is obviously wrong :(
> > I have used hexagonal unit cells containing 3 atoms. Cu.pz-d-rrkjus.UPF
> > pseudo potential was used in the calculation. It would be great if
> > somebody can suggest me something.
> > Following is the input file I used -
> >
> >  &system
> >     ibrav =4,
> >     celldm(1) =4.78076379, celldm(3)=2.44948974,
> >     nat= 3,
> >     ntyp= 1,
> >     nelec=33.0,
> >     nbnd=24,
> >     ecutwfc =25.0,
> >     occupations= 'smearing',
> >     smearing='gaussian',
> >     degauss=0.02
> >
> >  /
> >  &electrons
> >     diagonalization='$diago'
> >     conv_thr = 1.0e-8
> >     mixing_beta=0.7
> >  /
> >  ATOMIC_SPECIES
> >  Cu       63.55  Cu.pz-d-rrkjus.UPF
> >  ATOMIC_POSITIONS {bohr}
> >   Cu  0.0          0.0          0.0
> >   Cu  2.390381895  1.380087631  3.903477289
> >   Cu  4.780763790  2.760175261  7.806954578
> > K_POINTS (automatic)
> > 8 8 8  0 0 0
> > EOF
> > # complex bands of cu(111) along the 001 direction K_perp=0
> > cat > cu.cond.in << EOF
> >  &inputcond
> >     outdir='$TMP_DIR/'
> >     prefixl='cu'
> >     band_file ='bands.cu'
> >     ikind=0
> >     energy0=10.d0
> >     denergy=-0.2d0
> >     ewind=3.d0
> >     epsproj=1.d-7
> >  /
> >     1
> >    -1.0 1.732 -0.8165
> >     100
> > EOF
> >
> >
> > Regards,
> > Manoj
> >
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