Interfaces to calculators
Contents
Interfaces to calculators¶
The interfaces for VASP, WIEN2k, Quantum ESPRESSO (QE), ABINIT, Elk, SIESTA, CRYSTAL, DFTB+, TURBOMOLE, FHI-AIMS, and CASTEP are built in to the usual phonopy command. See the command options and how to invoke each of them at Choice of force calculator. LAMMPS interface is provided as an external tool by Abel Carreras.
List of force calculators¶
Short tutorials for the force calculators are found in the following pages.
- VASP & phonopy calculation
- Wien2k & phonopy calculation
- Quantum ESPRESSO (QE) & phonopy calculation
- Abinit & phonopy calculation
- Siesta & phonopy calculation
- Elk & phonopy calculation
- CRYSTAL & phonopy calculation
- DFTB+ & phonopy calculation
- TURBOMOLE & phonopy calculation
- CP2K & phonopy calculation
- FHI-aims & phonopy calculations
- CASTEP & phonopy calculation
- Fleur & phonopy calculation
The VASP DFPT interface reads vasprun.xml and creates FORCE_CONSTANTS file.
Physical unit system for calculator¶
Physical unit systems used for the calculators are as follows:
| Distance Atomic mass Force Force constants
-----------------------------------------------------------------
VASP | Angstrom AMU eV/Angstrom eV/Angstrom^2
WIEN2k | au (bohr) AMU mRy/au mRy/au^2
QE | au (bohr) AMU Ry/au Ry/au^2
ABINIT | au (bohr) AMU eV/Angstrom eV/Angstrom.au
SIESTA | au (bohr) AMU eV/Angstrom eV/Angstrom.au
Elk | au (bohr) AMU hartree/au hartree/au^2
CRYSTAL | Angstrom AMU eV/Angstrom eV/Angstrom^2
TURBOMOLE | au (bohr) AMU hartree/au hartree/au^2
CP2K | Angstrom AMU hartree/au hartree/Angstrom.au
FHI-AIMS | Angstrom AMU eV/Angstrom eV/Angstrom^2
Fleur | au (bohr) AMU hartree/au hartree/au^2
For these sets of physical properties, phonon frequency is calculated in THz.
Default file name, value, and conversion factor¶
Default unit cell file name for calculator¶
Without specifying -c option, default file name for unit cell is used as shown
below:
VASP | POSCAR
WIEN2k | case.struct
QE | unitcell.in
ABINIT | unitcell.in
SIESTA | input.fdf
Elk | elk.in
CRYSTAL | crystal.o
DFTB+ | geo.gen
TURBOMOLE | control
CP2K | unitcell.inp
FHI-AIMS | geometry.in
Fleur | fleur.in
Default displacement distances¶
Without specifying DISPLACEMENT_DISTANCE tag or --amplitude option, default
displacement distance is used when creating supercells with displacements
CREATE_DISPLACEMENTS = .TRUE. or -d option. The default value is dependent
on calculator, and the list is shown below:
VASP | 0.01 Angstrom
WIEN2k | 0.02 au (bohr)
QE | 0.02 au (bohr)
ABINIT | 0.02 au (bohr)
SIESTA | 0.02 au (bohr)
Elk | 0.02 au (bohr)
CRYSTAL | 0.01 Angstrom
DFTB+ | 0.01 au (bohr)
TURBOMOLE | 0.02 au (bohr)
CP2K | 0.01 Angstrom
FHI-AIMS | 0.01 Angstrom
Fleur | 0.02 au (bohr)
Default unit conversion factor of phonon frequency to THz¶
VASP | 15.633302
WIEN2k | 3.44595837
QE | 108.97077
ABINIT | 21.49068
SIESTA | 21.49068
Elk | 154.10794
CRYSTAL | 15.633302
DFTB+ | 154.10794
TURBOMOLE | 154.10794
CP2K | 112.10516
FHI-AIMS | 15.633302
Fleur | 154.10794
Default unit conversion factor for non-analytical term correction¶
VASP | 14.399652
WIEN2k | 2000
QE | 2
ABINIT | 51.422090
SIESTA | 51.422090
Elk | 1
CRYSTAL | 14.399652
DFTB+ | 14.399652
TURBOMOLE | 1
CP2K | None (N/A)
FHI-AIMS | 14.399652
Fleur | 1 (but feature N/A)