ABINIT Discussion Forums

Dear Users,

This is the first time I deal with plotting phonons frequencies in wurtzite structure and I need the coordinates of the high symmetry points for the hexagonal
path ,
I'd appreciate your help,
N.Bruno

See the website http://www.cryst.ehu.es/, specifically the kvec tool, it draws nice pictures of the Brillouin zone for each space group and also gives you coordinates.

Many thanks for your reply.......the website is very helpful.

Dear Users,
After I modified the trf2_5.in from cubic to wurtzute structure, I obtained a strange plott of the frequencies,
Did someone get this problem before?


here is attached my input file:

!Input file for the anaddb code. Analysis of the SiO2 DDB

!Flags
ifcflag 1 ! Interatomic force constant flag

!Wavevector grid number 1 (coarse grid, from DDB)
brav 4 ! Bravais Lattice : 1-S.C., 2-F.C., 3-B.C., 4-Hex.)
ngqpt 4 4 4 ! Monkhorst-Pack indices
nqshft 1 ! number of q-points in repeated basic q-cell
q1shft 3*0.0

!Effective charges
asr 2 ! Acoustic Sum Rule. 1 => imposed asymetrically
chneut 1 ! Charge neutrality requirement for effective charges.

!Interatomic force constant info
dipdip 1 ! Dipole-dipole interaction treatment

!Phonon band structure output for band2eps - See note near end for
! dealing with gamma LO-TO splitting issue.
eivec 4


!Wavevector list number 1 (Reduced coordinates and normalization factor)
nph1l 176 ! number of phonons in list 1
qph1l 0.0 0.0 0.0 1.0 ! (G point)
0.015 0.015 0.03 1.0
0.030 0.030 0.06 1.0
0.045 0.045 0.09 1.0
0.060 0.060 0.12 1.0
0.075 0.075 0.15 1.0
0.090 0.090 0.18 1.0
0.105 0.105 0.21 1.0
0.120 0.120 0.24 1.0
0.135 0.135 0.27 1.0
0.150 0.150 0.30 1.0
0.165 0.165 0.33 1.0
0.180 0.180 0.36 1.0
0.195 0.195 0.39 1.0
0.210 0.210 0.42 1.0
0.225 0.225 0.45 1.0
0.240 0.240 0.48 1.0
0.255 0.255 0.51 1.0
0.270 0.270 0.54 1.0
0.285 0.285 0.57 1.0
0.300 0.300 0.60 1.0
0.315 0.315 0.63 1.0
0.330 0.330 0.66 1.0
0.345 0.345 0.69 1.0
0.360 0.360 0.72 1.0
0.667 0.337 0.0 1.0 ! (K point)
0.620 0.24 0.620 1.0 !Direction U-->X
0.615 0.23 0.615 1.0
0.610 0.22 0.610 1.0
0.605 0.21 0.605 1.0
0.600 0.20 0.600 1.0
0.595 0.19 0.595 1.0
0.590 0.18 0.590 1.0
0.585 0.17 0.585 1.0
0.580 0.16 0.580 1.0
0.575 0.15 0.575 1.0
0.570 0.14 0.570 1.0
0.565 0.13 0.565 1.0
0.560 0.12 0.560 1.0
0.555 0.11 0.555 1.0
0.550 0.10 0.550 1.0
0.545 0.09 0.545 1.0
0.540 0.08 0.540 1.0
0.535 0.07 0.535 1.0
0.530 0.06 0.530 1.0
0.525 0.05 0.525 1.0
0.520 0.04 0.520 1.0
0.515 0.03 0.515 1.0
0.510 0.02 0.510 1.0
0.505 0.01 0.505 1.0
0.5 0.0 0.0 1.0 ! (M point )
0.48 0.00 0.48 1.0
0.46 0.00 0.46 1.0
0.44 0.00 0.44 1.0
0.42 0.00 0.42 1.0
0.40 0.00 0.40 1.0
0.38 0.00 0.38 1.0
0.36 0.00 0.36 1.0
0.34 0.00 0.34 1.0
0.32 0.00 0.32 1.0
0.30 0.00 0.30 1.0
0.28 0.00 0.28 1.0
0.26 0.00 0.26 1.0
0.24 0.00 0.24 1.0
0.22 0.00 0.22 1.0
0.20 0.00 0.20 1.0
0.18 0.00 0.18 1.0
0.16 0.00 0.16 1.0
0.14 0.00 0.14 1.0
0.12 0.00 0.12 1.0
0.10 0.00 0.10 1.0
0.08 0.00 0.08 1.0
0.06 0.00 0.06 1.0
0.04 0.00 0.04 1.0
0.02 0.00 0.02 1.0
0.0 0.0 0.0 1.0 ! (G point )
0.02 0.02 0.02 1.0
0.04 0.04 0.04 1.0
0.06 0.06 0.06 1.0
0.08 0.08 0.08 1.0
0.10 0.10 0.10 1.0
0.12 0.12 0.12 1.0
0.14 0.14 0.14 1.0
0.16 0.16 0.16 1.0
0.18 0.18 0.18 1.0
0.20 0.20 0.20 1.0
0.22 0.22 0.22 1.0
0.24 0.24 0.24 1.0
0.26 0.26 0.26 1.0
0.28 0.28 0.28 1.0
0.30 0.30 0.30 1.0
0.32 0.32 0.32 1.0
0.34 0.34 0.34 1.0
0.36 0.36 0.36 1.0
0.38 0.38 0.38 1.0
0.40 0.40 0.40 1.0
0.42 0.42 0.42 1.0
0.44 0.44 0.44 1.0
0.46 0.46 0.46 1.0
0.48 0.48 0.48 1.0
0.0 0.0 0.5 1.0 ! (A point)
0.5 0.48 0.5 1.0
0.5 0.46 0.5 1.0
0.5 0.44 0.5 1.0
0.5 0.42 0.5 1.0
0.5 0.40 0.5 1.0
0.5 0.38 0.5 1.0
0.5 0.36 0.5 1.0
0.5 0.34 0.5 1.0
0.5 0.32 0.5 1.0
0.5 0.30 0.5 1.0
0.5 0.28 0.5 1.0
0.5 0.26 0.5 1.0
0.5 0.24 0.5 1.0
0.5 0.22 0.5 1.0
0.5 0.20 0.5 1.0
0.5 0.18 0.5 1.0
0.5 0.16 0.5 1.0
0.5 0.14 0.5 1.0
0.5 0.12 0.5 1.0
0.5 0.10 0.5 1.0
0.5 0.08 0.5 1.0
0.5 0.06 0.5 1.0
0.5 0.04 0.5 1.0
0.5 0.02 0.5 1.0
0.667 0.337 0.5 1.0 ! (H point)
0.5 0.01 0.51 1.0
0.5 0.02 0.52 1.0
0.5 0.03 0.53 1.0
0.5 0.04 0.54 1.0
0.5 0.05 0.55 1.0
0.5 0.06 0.56 1.0
0.5 0.07 0.57 1.0
0.5 0.08 0.58 1.0
0.5 0.09 0.59 1.0
0.5 0.10 0.60 1.0
0.5 0.11 0.61 1.0
0.5 0.12 0.62 1.0
0.5 0.13 0.63 1.0
0.5 0.14 0.64 1.0
0.5 0.15 0.65 1.0
0.5 0.16 0.66 1.0
0.5 0.17 0.67 1.0
0.5 0.18 0.68 1.0
0.5 0.19 0.69 1.0
0.5 0.20 0.70 1.0
0.5 0.21 0.71 1.0
0.5 0.22 0.72 1.0
0.5 0.23 0.73 1.0
0.5 0.24 0.74 1.0
0.5 0.0 0.5 1.0 ! (L point)
0.5 0.26 0.74 1.0
0.5 0.27 0.73 1.0
0.5 0.28 0.72 1.0
0.5 0.29 0.71 1.0
0.5 0.30 0.70 1.0
0.5 0.31 0.69 1.0
0.5 0.32 0.68 1.0
0.5 0.33 0.67 1.0
0.5 0.34 0.66 1.0
0.5 0.35 0.65 1.0
0.5 0.36 0.64 1.0
0.5 0.37 0.63 1.0
0.5 0.38 0.62 1.0
0.5 0.39 0.61 1.0
0.5 0.40 0.60 1.0
0.5 0.41 0.59 1.0
0.5 0.42 0.58 1.0
0.5 0.43 0.57 1.0
0.5 0.44 0.56 1.0
0.5 0.45 0.55 1.0
0.5 0.46 0.54 1.0
0.5 0.47 0.53 1.0
0.5 0.48 0.52 1.0
0.5 0.49 0.51 1.0
0.0 0.0 0.5 1.0 ! (A point)


!Wavevector list number 2 (Cartesian directions for non-analytic gamma phonons)

!The output for this calculation must be cut-and-pasted into the
! t59_out.freq file to be used as band2eps input to get proper LO-TO
! splitting at gamma. Note that gamma occurrs twice.

nph2l 1 ! number of directions in list 2

qph2l 1.0 0.0 0.0 0.0
# This line added when defaults were changed (v5.3) to keep the previous, old behaviour
symdynmat 0

From only your anaddb input file but no output, we can't tell what it is in your output that you consider strange. You need to post more information and a more specific question.

Dear Dr. jzwanzig,

As you can see in the input file, I had changed in qph1l the coordinates for the high symmetry points and I kept those of the
the points situated in each segment and corresponding to the cubic structure. I wonder I am correct? If not how can I calculate them?
Thanks in advance,
N.Bruno

Dear Bruno,

Maybe you can show us the phonon bandstructure you obtain?

Anyway since you have sharp breaking between hight symmetry point
( like 0.667 0.337 0.0 1.0 ! (K point)
0.620 0.24 0.620 1.0 !Direction U-->X) I also expect you to have similar sharp change in your phonon bandstructure.

For an hexagonal path, this is the typical path: K-Gamma-M-K-H-A-L-H-L-M-Gamma-A (1/3 1/3 0 0 0 0 1/2 0 0 1/3 1/3 0 1/3 1/3 1/2 0 0 1/2 1/2 0 1/2 1/3 1/3 1/2 1/2 0 1/2 1/2 0 0 0 0 0 0 0 1/2 )

You can look at the abinit variable kptbounds for more informations

http://www.abinit.org/documentation/helpfiles/for-v6.10/input_variables/vargs.html#kptbounds

Have a good day

Samuel.