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["Wu Rongqin" <g0203654@nus.edu.sg>]

Dear all,

I calculated the phonon at gamma point of SrTiO3, the result seem to puzzles me!

See blow:

The -97.44653 cm(-1) should be correspondent to the soft norm. but the -6.04665 cm(-1) frequency at gamma should be, in my opinion, zero. I find increasing k-point and energy cutoff cannot get the zero frequency at gamma! The lattice constant has been correctly calculated. Hope for your comments

Rongqin

Phonon wavevector (reduced coordinates) :  0.00000  0.00000  0.00000

 Phonon energies in Hartree :

  -4.439991E-04 -4.439980E-04 -4.439956E-04 -2.755056E-05 -2.753126E-05

  -2.752154E-05  1.258732E-04  1.258732E-04  1.258732E-04  8.695282E-04

   8.695283E-04  8.695296E-04  2.779686E-03  2.779686E-03  2.779686E-03

 Phonon frequencies in cm-1    :

- -9.744653E+01 -9.744630E+01 -9.744577E+01 -6.046650E+00 -6.042413E+00

- -6.040279E+00  2.762598E+01  2.762598E+01  2.762598E+01  1.908394E+02

-  1.908394E+02  1.908397E+02  6.100705E+02  6.100705E+02  6.100707E+02

 

  Phonon at Gamma, with non-analyticity in the

  direction (cartesian coordinates)  1.00000  0.00000  0.00000

 Phonon energies in Hartree :

  -4.439980E-04 -4.439956E-04 -2.814448E-05 -2.753126E-05 -2.752154E-05

   1.258732E-04  1.258732E-04  1.258732E-04  5.621172E-04  8.695282E-04

   8.695296E-04  1.540756E-03  2.779686E-03  2.779686E-03  3.648319E-03

 Phonon frequencies in cm-1    :

- -9.744630E+01 -9.744577E+01 -6.176999E+00 -6.042413E+00 -6.040279E+00

-  2.762598E+01  2.762598E+01  2.762598E+01  1.233705E+02  1.908394E+02

-  1.908397E+02  3.381569E+02  6.100705E+02  6.100705E+02  8.007135E+02