5 votes

Phonon calculations using DFPT

Clarifiation: At first let me point out that Phonons can be calculated either using DFPT, or Finite Displacement methods. You can refer to the extensive answer by ProfM Are there differences in ...
Jaafar Mehrez's user avatar
4 votes

Thermal Properties Calculated with Phonopy

$N_A$ stands for Avogadro's number. Energies are reported in kJ/mol, so they are technically for a mole of unit cells. Conversion factors to other units (kcal/mol, eV, Hartree, etc.) can be found or ...
Kristof Bal's user avatar
  • 1,331
3 votes

Exploring Phonon Dispersion in Two-Dimensional Materials: Analytical Techniques and Mode Identification

Do you know what longitudinal, transverse, acoustic, and optical mean in this context? Or you want a code that can tell you what they are? If you know what they mean, you can plot the displacements ...
Tyler Sterling's user avatar
2 votes

Why dipole correction does not work in VASP DFPT + phonopy calculation for a stable 2D material

I assume the problem has to do with the fact that the long-range Coulomb interaction looks different in 2D than it does in 3D. Dimensionality enters in Fourier space and yields a different asymptotic ...
flokno's user avatar
  • 136
2 votes

Getting the Phonon Dispersion Using fix phonon in LAMMPS

I was able to compile the phana code but fix phonon just gave a peak around zero. I raised an issue on the GitHub repository and ...
Mohamed's user avatar
  • 695
1 vote

Inconsistencies in Phonon Dispersion Results Using Phonopy DFPT with Different Supercell Sizes

Based on your comments above, it looks like you increased k-point sampling for the 3x3x1 supercell and found the correct dispersions. It seems like the imaginary modes in the smaller cells is due to ...
Tyler Sterling's user avatar

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