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标题: vasp计算四方相P42/nmc HfO2声子频率过低，晶格常数偏高，如何解决？ [打印本页]

作者
Author: crystalcat 时间: 2026-3-14 18:26
标题: vasp计算四方相P42/nmc HfO2声子频率过低，晶格常数偏高，如何解决？
本帖最后由 crystalcat 于 2026-3-14 19:31 编辑

使用了PAW_PBE （GGA）赝势， Hf_sv，O
EDIFF=1E-08，EDIFFG=-0.001，已经充分迭代到收敛，kspace取0.03。
声子计算采用有限差分方法IBRION =  6
最低声子频率48cm-1远低于参考文献给出的一百多cm-1,不知道如何解决？是什么引起？
不胜感激。

INCAR.relax
Global Parameters
ISTART =  1          (Read existing wavefunction, if there)
ISPIN  =  1          (Non-Spin polarised DFT)
# ICHARG =  11       (Non-self-consistent: GGA/LDA band structures)
LREAL  = .FALSE.    (Projection operators: automatic)
ENCUT  =  520       (Cut-off energy for plane wave basis set, in eV)
# PREC =  Accurate (Precision level: Normal or Accurate, set Accurate when perform structure lattice relaxation calculation)
LWAVE  = .TRUE.       (Write WAVECAR or not)
LCHARG = .TRUE.       (Write CHGCAR or not)
ADDGRID= .TRUE.       (Increase grid, helps GGA convergence)
LASPH  = .TRUE.       (Give more accurate total energies and band structure calculations)
PREC = Accurate    (Accurate strictly avoids any aliasing or wrap around errors)
# LVTOT  = .TRUE.    (Write total electrostatic potential into LOCPOT or not)
# LVHAR  = .TRUE.    (Write ionic + Hartree electrostatic potential into LOCPOT or not)
# NELECT =          (No. of electrons: charged cells, be careful)
# LPLANE = .TRUE.    (Real space distribution, supercells)
# NWRITE = 2          (Medium-level output)
# KPAR = 2          (Divides k-grid into separate groups)
# NGXF = 300       (FFT grid mesh density for nice charge/potential plots)
# NGYF = 300       (FFT grid mesh density for nice charge/potential plots)
# NGZF = 300       (FFT grid mesh density for nice charge/potential plots)
EDIFF = 1E-08
Lattice Relaxation
NSW =  300       (number of ionic steps)
ISMEAR =  0          (gaussian smearing method )
SIGMA  =  0.05       (please check the width of the smearing)
IBRION =  2          (Algorithm: 0-MD, 1-Quasi-New, 2-CG)
ISIF =  3          (optimize atomic coordinates and lattice parameters)
EDIFFG = -1E-03    (Ionic convergence, eV/A)

INCAR.phonon
ISMEAR =  0          (Gaussian smearing)
SIGMA  =  0.01       (Smearing value in eV)
EDIFF  =  1E-08       (SCF energy convergence, in eV)
PREC =  Accurate    (Precision level)
ENCUT  =  520       (Cut-off energy for plane wave basis set, in eV)
IALGO  =  38          (Davidson block iteration scheme)
LREAL  = .FALSE.    (Projection operators: false)
LWAVE  = .FALSE.    (Write WAVECAR or not)
LCHARG = .FALSE.    (Write CHGCAR or not)
ADDGRID= .TRUE.       (Increase grid, helps GGA convergence)
IBRION =  6          (Calculate phonon frequencies using finite differences approach)
LPHON_DISPERSION = T (Calculate phonon dispersion along the q-point path supplied in file QPOINTS)
PHON_NWRITE = -3    (Both phonon eigenvectors and phonon frequencies are written for each q point)

POSCAR:
Hf2 O4
1.00000000000000
   3.5941944686576677 0.0000000000000000 0.0000000000000000
   0.0000000000000000 3.5941944686576677 0.0000000000000000
   0.0000000000000000 0.0000000000000000 5.2305425368624849
Hf O
   2    4
Direct
  0.5000000000000000  0.5000000000000000  0.5000000000000000
  0.0000000000000000  0.0000000000000000  0.0000000000000000
  0.0000000000000000  0.5000000000000000  0.6957736386243809
  0.5000000000000000  0.0000000000000000  0.8042263613756191
  0.5000000000000000  0.0000000000000000  0.3042263913756216
  0.0000000000000000  0.5000000000000000  0.1957736086243784

  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00

伽马点最低光学支频率：

  14 f  = 1.453087 THz    9.130013 2PiTHz 48.469753 cm-1    6.009481 meV
         X       Y       Z          dx       dy       dz
   1.797097  1.797097  2.615271    0.008617 0.208536 -0.000000
   0.000000  0.000000  0.000000    0.008617 0.208536 -0.000000
   0.000000  1.797097  3.639274 -0.000211 -0.675007 -0.000000
   1.797097  0.000000  4.206540 -0.000211 -0.675007 -0.000000
   1.797097  0.000000  1.591269 -0.027894 -0.005101 0.000000
   0.000000  1.797097  1.024002 -0.027894 -0.005101 -0.000000

  15 f  = 1.453087 THz    9.130013 2PiTHz 48.469753 cm-1    6.009481 meV
         X       Y       Z          dx       dy       dz
   1.797097  1.797097  2.615271    0.208536 -0.008617 -0.000000
   0.000000  0.000000  0.000000    0.208536 -0.008617 -0.000000
   0.000000  1.797097  3.639274 -0.005101 0.027894 -0.000000
   1.797097  0.000000  4.206540 -0.005101 0.027894 0.000000
   1.797097  0.000000  1.591269 -0.675007 0.000211 -0.000000
   0.000000  1.797097  1.024002 -0.675007 0.000211 -0.000000

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