Input File Description

File produced by q2r containing force constants (needed)
It is the same as in the input of q2r.x (+ the .xml extension
if the dynamical matrices produced by ph.x were in xml
format). No default value: must be specified.
         

Indicates the type of Acoustic Sum Rule imposed.

Allowed values:
            

'no' :

no Acoustic Sum Rules imposed (default)
            

'simple' :

previous implementation of the asr used
(3 translational asr imposed by correction of
 the diagonal elements of the force constants matrix)
            

'crystal' :

3 translational asr imposed by optimized
correction of the force constants (projection)
            

'all' :

3 translational asr + 3 rotational asr + 15 Huang
conditions for vanishing stress tensor, imposed by
optimized correction of the force constants (projection).
Remember to set write_lr = .true. to write long-range
force constants into file when running q2r and set read_lr = .true. when running matdyn in the case of
infrared-active solids. (See npj Comput Mater 8, 236 (2022))
            

'one-dim' :

3 translational asr + 1 rotational asr imposed
by optimized correction of the dyn. mat. (the
rotation axis is the direction of periodicity; it
will work only if this axis considered is one of
the Cartesian axis).
            

'zero-dim' :

3 translational asr + 3 rotational asr imposed
by optimized correction of the dyn. mat.
            

Note that in certain cases, not all the rotational asr
can be applied (e.g. if there are only 2 atoms in a
molecule or if all the atoms are aligned, etc.).
In these cases the supplementary asr are cancelled
during the orthonormalization procedure (see below).
            

if .true. 15 Huang conditions for vanishing stress
tensor are included in asr = 'all'.
         

if .true. calculate phonon Density of States (DOS)
using tetrahedra and a uniform q-point grid (see below)
NB: may not work properly in noncubic materials

if .false. calculate phonon bands from the list of q-points
supplied in input (default)
         

uniform q-point grid for DOS calculation (includes q=0)
(must be specified if dos = .true., ignored otherwise)
         

energy step, in cm-1, for DOS calculation: from min
to max phonon energy (default: 1 cm-1 if ndos, see
below, is not specified)
         

number of energy steps for DOS calculations
(default: calculated from deltaE if not specified)
         

DOS broadening in cm-1

Default: 0 - meaning use tetrahedra
         

output file for dos (default: 'matdyn.dos')
the dos is in states/cm-1 plotted vs omega in cm(-1)
and is normalised to 3*nat, i.e. the number of phonons
         

output file for frequencies (default: 'matdyn.freq')
         

output file for normalized phonon displacements
(default: 'matdyn.modes'). The normalized phonon displacements
are the eigenvectors divided by the square root of the mass,
then normalized. As such they are not orthogonal.
         

output file for phonon eigenvectors (default: 'matdyn.eig')
The phonon eigenvectors are the eigenvectors of the dynamical
matrix. They are orthogonal.
         

output file for dynamical matrix (default: ' ' i.e. not written)
         

supercell lattice vectors - must form a superlattice of the
original lattice (default: use original cell)
         

supercell lattice vectors are original cell vectors times
l1, l2, l3 respectively (default: 1, ignored if at specified)
         

number of atom types in the supercell
(default: ntyp of the original cell)
         

masses of atoms in the supercell (a.m.u.), one per atom type
(default: use masses read from file flfrc)
         

read  atomic positions of the supercell from input
(used to specify different masses) (default: .false.)
         

write atomic positions of the supercell to file fltau
(default: fltau = ' ', do not write)
         

if .true. interpolates also the el-ph coefficients
         

if .true. the q points are given in band form:
only the first and last point of one or more lines
are given. See below. (default: .false.).
         

if .true. input q points are in crystalline
coordinates (default: .false.)
         

use similarity of the displacements to order
frequencies  (default: .false.)

NB: You cannot use this option with the symmetry
analysis of the modes.
         

if .true. the ifc come from the finite displacement calculation
         

add non analitic contributions to the interatomic force
constants if finite displacement method is used (as in Wang et al.
PRB 85, 224303 (2012)) [to be used in conjunction with fd.x]
         

if .true., no symmetry and no time reversal are imposed
         

set to .true. to activate two-dimensional treatment of LO-TO splitting
         

if .true. do not apply LO-TO splitting for q=0
(default: .false.)
         

if .true. read also long-range force constants when they exist in
force constant file. This is required when enforcing asr = 'all'
for infrared-active solids.
         

if .true. write force constants with asr imposed into file.
The filename would be flfrc+".matdyn". The long-range part of
force constants will be not written.