The ABINIT Users Mailing List ( CLOSED )

["Kwan-Woo Lee" <kwlee@ucdavis.edu>]

Dear ABINIT Users,

I have a few questions.  Could you help me?

1) Did you use the ifc-code in order to obtain a phonon dispersion
relation?
  I don't exactly understand the required step.
 First, obtain the DDB files using ABINIT main code at a few symmetry
points.
 Second, merge the DDB files using mrgddb code.
 Third,  obtain the final results using ifc code.
 
Is the  step correct ?
 

2)  Is there  one that have ever tried to obtain the phonon frequency, with
hcp-structure, contained E-field perturbation?  
I obtained it of several materials with the fcc structure, however I have
not solved the problem 
of hcp-structure.  This is a input file (also attached) of LiB with
hcp-structure.  (For non-E field perturbation,  I obtained the phonon
frequencies)

###########################################################################
ndtset   3 

# Specific to ground state calculation
kptopt1    1                     #1,2 or 3
mkmem1     0
tolvrs1    1.0d-18
  iscf1    5

# Response Function calculation : d/dk
rfelfd2    2
 rfdir2    1  0  0           # In the x-direction.

nqpt2      1
 qpt2      0.0  0.0  0.0     # For a Gamma point

getwfk2    -1
kptopt2     2

iscf2      -3
tolwfr2    1.0d-22

# To calculate RF, with q=0: E-field perturbation
rfphon3     1
rfatpol3    1   4
rfelfd3     3                 # only the generation of the first-order
response 
                                # to the electric field
rfdir3      1  1  1
kptopt3     2

nqpt3       1
 qpt3       0.0  0.0  0.0      # Gamma point

getwfk3    -2                  # Read the previous result(groundstate Cal.) 
getddk3    -1                  # Using the ouput of the dataset2

tolvrs3     1.0d-10
  iscf3     5

######################################################Common Input
variables
#Definition of the unit cell
acell 2*4.022  2.796 angstrom
                                    
rprim  0.86602540378  0.500  0.000  # Primitive vectors
      -0.86602540378  0.500  0.000
       0.000          0.000  1.000

#spgroup     194                     # the number of space group
# brvltt       1                          # from the table
chkprim       0
occopt        4
 ntype   2           # There are only three types of atom
zatnum  3   5      # The keyword "zatnum" refers to the atomic number of
the 
                        # possible type(s) of atom. 

#Definition of the atoms
natom  4            # There are four atoms
 type  2  2  1  1   # 
 xred               
   0.00 0.00 0.00   # Triplet giving the reduced coordinates of atom 1, in
Bohr
   0.00 0.00 0.50
   0.6666666666666666667 0.3333333333333333333 0.00 # of atom 2, in Bohr
   0.3333333333333333333 0.6666666666666666667 0.50   

#Definition of the planewave basis set
#ecut 10.0         # Maximal plane-wave kinetic energy cut-off, in Hartree
ecut  5.0
dilatmx 1.10

# Gives the number of band
nband   8           # Not determined.

#Definition of the k-point grid( afther testing, determined.)
#prtkpt  1          # to genertate "kptrlatt" and "shiftk"
kptrlatt  2   0   0      
           0   2   0
           0   0   3
nshiftk  1
shiftk  0.00000000  0.00000000  5.00000000E-01

#Definition of the SCF procedure
nstep 40           # Maximal number of SCF cycles

###########################################################################

If you have any hint,  please let me know it.
I will very apprecite for it.

Sincerely,

Kwan-Woo Lee

Attachment: lib_hcp.in
Description: lib_hcp.in