The ABINIT Users Mailing List ( CLOSED )

["Bo Qiu" <200210qb@gmail.com>]

Dear Users and Developlers,

Below are the input files I used for the calculation, thanks a lot!

trf2_1.in
=============================
   ndtset   15
#Set 1 : ground state self-consistency

  getwfk1   0            # Cancel default
  kptopt1   1            # Automatic generation of k points, taking
                         # into account the symmetry
    nqpt1   0            # Cancel default
  tolvrs1   1.0d-18      # SCF stopping criterion (modify default)
  rfphon1   0            # Cancel default

     nqpt   1            # One qpt for each dataset (only 0 or 1 allowed)
                         # This is the default for all datasets and must
                         #  be explicitly turned off for dataset 1.

     qpt2         0.00000000E+00  0.00000000E+00  0.00000000E+00
     qpt3         0.00000000E+00  0.00000000E+00  0.00000000E+00
     qpt4         2.50000000E-01  0.00000000E+00  0.00000000E+00
     qpt5         5.00000000E-01  0.00000000E+00  0.00000000E+00
     qpt6         2.50000000E-01  2.50000000E-01  0.00000000E+00
     qpt7         5.00000000E-01  2.50000000E-01  0.00000000E+00
     qpt8        -2.50000000E-01  2.50000000E-01  0.00000000E+00
     qpt9         5.00000000E-01  5.00000000E-01  0.00000000E+00
     qpt10        2.50000000E-01  2.50000000E-01  2.50000000E-01
     qpt11        5.00000000E-01  2.50000000E-01  2.50000000E-01
     qpt12       -2.50000000E-01  2.50000000E-01  2.50000000E-01
     qpt13        5.00000000E-01  5.00000000E-01  2.50000000E-01
     qpt14       -2.50000000E-01  5.00000000E-01  2.50000000E-01
     qpt15        5.00000000E-01  5.00000000E-01  5.00000000E-01

#Set 2 : Response function calculation of d/dk wave function 

    iscf2   -3         # Need this non-self-consistent option for d/dk
  kptopt2   2          # Modify default to use time-reversal symmetry
  rfphon2   0          # Cancel default
  rfelfd2   2          # Calculate d/dk wave function only
  tolvrs2   0.0        # Cancel default for d/dk
  tolwfr2   1.0d-22    # Use wave function residual criterion instead

#Set 3 : Response function calculation of Q=0 phonons and electric field pert.

  getddk3   2          # d/dk wave functions from last dataset
  kptopt3   2          # Modify default to use time-reversal symmetry
  rfelfd3   3          # Electric-field perturbation response only

#Sets 4-10 : Finite-wave-vector phonon calculations (defaults for all datasets)

   getwfk   1          # Use GS wave functions from dataset1
   kptopt   3          # Need full k-point set for finite-Q response
   rfphon   1          # Do phonon response
  rfatpol   1 2        # Treat displacements of all atoms
    rfdir   1 1 1      # Do all directions (symmetry will be used)
   tolvrs   1.0d-8     # This default is active for sets 3-10

#######################################################################
#Common input variables

#Definition of the unit cell
acell    19.988656880  19.988656880  19.988656880         # This is equivalent to   10.18 10.18 10.18
rprim    0.24005673565  0.00000000000  0.97075885969
        -0.12002836783  0.20789523142  0.97075885969
        -0.12002836783 -0.20789523142  0.97075885969


#spgroup 166


#Definition of the atom types
ntypat 2          # There is only one type of atom
znucl 83 52          # The keyword "znucl" refers to the atomic number of the 
                  # possible type(s) of atom. The pseudopotential(s) 
                  # mentioned in the "files" file must correspond
                  # to the type(s) of atom. Here, the only type is Silicon.
                         

#Definition of the atoms
natom 5           # There are two atoms
typat 2 2 1 1 2         # They both are of type 1, that is, Silicon.
xred    0.0000000000  0.0000000000  0.0000000000
        0.21079648582  0.21079648582  0.21079648582
        0.40055571131  0.40055571131  0.40055571131
        0.59944428869  0.59944428869  0.59944428869
        0.78920351418  0.78920351418  0.78920351418

#Definition of the planewave basis set

     ecut   6.0           # Maximal kinetic energy cut-off, in Hartree

#Definition of the k-point grid
    ngkpt   4  4  4          
  nshiftk   1              # Use one copy of grid only (default)
   shiftk   0.0 0.0 0.5    # This gives the usual fcc Monkhorst-Pack grid

#Definition of the SCF procedure
     iscf   5          # Self-consistent calculation, using algorithm 5
    nstep   25         # Maximal number of SCF cycles
   diemac   9.0        # Although this is not mandatory, it is worth to

=============================

trf2_7.in
==============================
!Flags
 ifcflag   1     ! Interatomic force constant flag
 thmflag   1     ! Thermodynamical properties flag

!Wavevector grid number 1 (coarse grid, from DDB)
  brav    1      ! 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   1     ! Acoustic Sum Rule. 1 => imposed asymetrically
  chneut   1     ! Charge neutrality requirement for effective charges.

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

!Wavevector grid number 2 (series of fine grids, extrapolated from interat forces)
  ng2qpt   20 20 20  ! sample the BZ up to ngqpt2
  ngrids   5         ! number of grids of increasing size
  q2shft   3*0.0

!Thermal information
  nchan   1250   ! # of channels for the DOS with channel width 1 cm-1
  nwchan  5      ! # of different channel widths from this integer down to 1 cm-1
  thmtol  0.120  ! Tolerance on thermodynamical function fluctuations
  ntemper 10     ! Number of temperatures
  temperinc 20.  ! Increment of temperature in K for temperature dependency
  tempermin 20.  ! Minimal temperature in Kelvin

==============================

Sincerely,

Bo

On Thu, Apr 3, 2008 at 9:29 PM, Bo Qiu <200210qb@gmail.com> wrote:

Dear Users and developlers,

I'm trying to calculate Phonon DOS for Bi2Te3 which has a rhombohedral structure, space group 166.

I followed the tutorial on Response functions #2 step by step:
1. generate k points using script similar to trf2_2.in,
2. copied k points from trf2_2.out and copy them to trf2_1.in as  kpoints.
3. run trf2_1.in to get DDBs.
4. mrgddb
5. anaddb trf2_7.in

However, when I got to the 5th step, I got following error out of the log file of trf2_7:
====================================
Calculation of the interatomic forces

-begin at tcpu      0.090  and twall      0.114 sec
 ewald9 : ERROR -
  The determinant of the dielectrix matrix, detdlt=    0.000000E+00 is smaller than 1.0d-6.
  The use of the dipole-dipole model for interatomic force constants is not possible.
  It is likely that you have not treated the electric field perturbations,
  because you not are dealing with an insulator, so that
  your dielectric matrix was simply set to zero in the Derivative DataBase.
  Action : set the input variable dipdip to 0 .

 leave_new : decision taken to exit ...
====================================

Actually I had specified one data set to treat electric field perturbation at gamma point in the trf2_1.in file. Then I went back to check trf2_1.out, I found there were warnings in output of every data set (corresponding to every qpoint):

chkph3 : WARNING -
  The dynamical matrix was incomplete : phonon frequencies may be wrong ...

However, I checked with the trf2_1.out of the tutorial AlAs case, for exactly the same specifications of input variables, there were not such warnings in the output file at all.

I've tried for quite a while but still cannot get a clue, could you please help me with this problem? I appreciate your kind help!

--
Thanks and Best Wishes.

Sincerely yours,
Bo Qiu
http://web.ics.purdue.edu/~qiub/homepage/

-- 
Thanks and Best Wishes.

Sincerely yours,
Bo Qiu
http://web.ics.purdue.edu/~qiub/homepage/