[QE-users] phonon linewidth calculation
Lorenzo Paulatto
lorenzo.paulatto at cnrs.fr
Wed Jun 11 08:29:40 CEST 2025
> This raises the question: Is it in fact only possible to calculate
> phonon linewidth just for metalic systems?
Electron-phonon coupling requires a Fermi surface, if there is a gap,
adding a smearing won't help. I guess you
want to simulate a doped semiconductor, in this case the el-ph coupling
is strongly dependent on the doping concentration. If you add the doping
as a net charge in the pw.x, it can in principle be done, but it will
never converge.
However, this kind of problem can be simulated with the Wannier-function
based codes. That can be plugged on QE there is EPW in the QE
distribution, PERTURBO <https://perturbo-code.github.io/index.html>
which is more or less a fork, and epiq
<https://the-epiq-team.gitlab.io/epiq-site/> which is a completely
independent implementation.
hth
>
>
> El mar, 10 jun 2025 a las 2:14, Lorenzo Paulatto
> (<lorenzo.paulatto at cnrs.fr>) escribió:
>
> I notice now that you have a ridiculous E_Fermi shift of 550 Ry,
> is your material by any chance an insulator, but you are using
> occupation='smearing'? If you have a gap, you must use
> occupation='fixed' in phonon. If you want to have magnetization,
> you will have to specify in pw input the total magnetization.
>
> hth
>
> On 09/06/2025 11:05, Ivan Dario Arellano Ramirez wrote:
>> Dear Lorenzo,
>>
>> I tried the settings you suggested:
>>
>> nmix_ph=10
>> alpha_mix=.25
>>
>> and conv_thr = 1.0d-12 for scf calculation
>>
>> however, the phonon calculation using ph.x still fails to converge.
>>
>> I then increased the nmix_ph up to 20 and decreased the alpha_mix
>> up to .1 but the issue persists.
>>
>> El sáb, 7 jun 2025 a las 7:14, Lorenzo Paulatto
>> (<lorenzo.paulatto at cnrs.fr>) escribió:
>>
>> Hhelo,
>>
>> increase nmix_ph and reduce alpha_mix, in a difficult case
>> recently I have used:
>>
>> nmix_ph=10
>> alpha_mix=.25
>>
>> Also, the convergence of the scf process in pw.x should be
>> tighter, something like
>> conv_thr = 1.0d-12
>>
>> Because the total energy is variational, but the phonons are
>> not, they converge much slower with this threshold.
>>
>> hth
>>
>>
>>
>> On 06/06/2025 21:48, Ivan Dario Arellano Ramirez wrote:
>>> I QE users
>>>
>>> I want to calculate the phonon linewidth for InN. I am
>>> following two tutorials. However, in both cases, I encounter
>>> the same issue: no convergence when using the ph.x module.
>>>
>>> Pert. # 1: Fermi energy shift (Ry) = -5.5393E+02
>>> 0.0000E+00
>>>
>>> iter # 150 total cpu time : 13815.8 secs av.it
>>> <http://av.it>.: 5.3
>>> thresh= 4.679E-04 alpha_mix = 0.700 |ddv_scf|^2 =
>>> 4.318E-06
>>>
>>> End of self-consistent calculation
>>>
>>> No convergence has been achieved
>>>
>>>
>>> This is an overview of the two approaches I followed:
>>>
>>> 1) perform very dense scf calculation with la2F=.true. in
>>> &systems (Likely, I am exceeding the maximum of 40000 k points)
>>> 2) normal scf on coarser k-mesh
>>> 3) phonon calculation using ph.x
>>> 4) Inverse Fourier transform of dynamical matrix and the
>>> phonon linewidth using q2r.x
>>> 5) Fourier transform to obtain dynamical matrix and the
>>> phonon linewidth using matdyn.x
>>>
>>> The other tutorial proposed an initial scf calculation
>>> followed by an nscf calculation with la2F=.true. the rest of
>>> steps are the same.
>>>
>>> Here are all the inputs.
>>>
>>> Any suggestions or insights would be greatly appreciated.
>>>
>>>
>>> 1) very dense k-mesh scf
>>>
>>> &control
>>> calculation = 'scf'
>>> restart_mode='from_scratch',
>>> prefix='inn_ep',
>>> tstress = .true.
>>> tprnfor = .true.
>>> pseudo_dir = '/home/pps/pbe.0.3.1/PSEUDOPOTENTIALS/',
>>> outdir='./tmp'
>>> verbosity = 'high'
>>> etot_conv_thr = 1.d-6
>>> forc_conv_thr = 1.d-5
>>> /
>>> &system
>>> ibrav = 0,
>>> nat= 4,
>>> ntyp= 2,
>>> ecutwfc = 90,
>>> ecutrho = 900,
>>> occupations='smearing',
>>> smearing='m-v',
>>> degauss=0.02,
>>> la2F = .true.
>>> /
>>> &electrons
>>> conv_thr = 1.0d-8
>>> electron_maxstep = 200,
>>> mixing_mode = 'plain'
>>> mixing_beta = 0.3D0
>>> diagonalization = 'david'
>>> /
>>> ATOMIC_SPECIES
>>> In 114.818 In.pbe-dn-rrkjus_psl.1.0.0.UPF
>>> N 14.007 N.pbe-n-rrkjus_psl.1.0.0.UPF
>>> CELL_PARAMETERS angstrom
>>> 1.793358573 -3.106188164 0.000000000
>>> 1.793358573 3.106188164 0.000000000
>>> 0.000000000 0.000000000 5.799337066
>>>
>>> ATOMIC_POSITIONS crystal
>>> In 0.3333330000 0.6666670000
>>> -0.0019331848
>>> In 0.6666670000 0.3333330000
>>> 0.4980668152
>>> N 0.3333330000 0.6666670000
>>> 0.3767331848
>>> N 0.6666670000 0.3333330000
>>> 0.8767331848
>>> K_POINTS automatic
>>> 45 45 36 0 0 0
>>>
>>> 2) normal scf
>>>
>>> &control
>>> calculation = 'scf'
>>> restart_mode='from_scratch',
>>> prefix='inn_ep',
>>> tstress = .true.
>>> tprnfor = .true.
>>> pseudo_dir = '/home/pps/pbe.0.3.1/PSEUDOPOTENTIALS/',
>>> outdir='./tmp'
>>> verbosity = 'high'
>>> etot_conv_thr = 1.d-6
>>> forc_conv_thr = 1.d-5
>>> /
>>> &system
>>> ibrav = 0,
>>> nat= 4,
>>> ntyp= 2,
>>> ecutwfc = 90,
>>> ecutrho = 900,
>>> occupations='smearing',
>>> smearing='m-v',
>>> degauss=0.02,
>>> /
>>> &electrons
>>> conv_thr = 1.0d-8
>>> electron_maxstep = 200,
>>> mixing_mode = 'plain'
>>> mixing_beta = 0.3D0
>>> diagonalization = 'david'
>>> /
>>> ATOMIC_SPECIES
>>> In 114.818 In.pbe-dn-rrkjus_psl.1.0.0.UPF
>>> N 14.007 N.pbe-n-rrkjus_psl.1.0.0.UPF
>>> CELL_PARAMETERS angstrom
>>> 1.793358573 -3.106188164 0.000000000
>>> 1.793358573 3.106188164 0.000000000
>>> 0.000000000 0.000000000 5.799337066
>>>
>>> ATOMIC_POSITIONS crystal
>>> In 0.3333330000 0.6666670000
>>> -0.0019331848
>>> In 0.6666670000 0.3333330000
>>> 0.4980668152
>>> N 0.3333330000 0.6666670000
>>> 0.3767331848
>>> N 0.6666670000 0.3333330000
>>> 0.8767331848
>>> K_POINTS automatic
>>> 15 15 12 0 0 0
>>>
>>> 3) phonon calculation
>>>
>>> Phonons of InN at G!=0
>>> &inputph
>>> tr2_ph = 1.0d-14,
>>> ldisp = .true.,
>>> prefix = 'inn_ep',
>>> recover = .true.
>>> fildyn = 'inn-ph.dyn',
>>> fildvscf = 'inndv'
>>> nq1 = 5,
>>> nq2 = 5,
>>> nq3 = 3,
>>> electron_phonon = 'interpolated'
>>> el_ph_nsigma = 10
>>> el_ph_sigma = 0.02
>>> amass(1) = 114.818,
>>> amass(2) = 14.007,
>>> outdir = './tmp'
>>> /
>>>
>>> 4) Inverse Fourier Transform
>>>
>>> &INPUT
>>> fildyn = 'inn-ph.dyn',
>>> zasr = 'crystal',
>>> flfrc = 'inn-ph.fc',
>>> la2F = .true.
>>> /
>>>
>>> 5) Fourier Transform
>>>
>>> &input
>>> asr = 'crystal',
>>> flfrc = 'inn-ph.fc',
>>> flfrq = 'inn.band.freq'
>>> flvec = 'inn.band.modes'
>>> amass(1) = 114.818,
>>> amass(2) = 14.007,
>>> q_in_band_form = .true.
>>> la2F = .true.
>>> /
>>> 8
>>> 0.0000000000 0.0000000000 0.0000000000 40 ! Gamma
>>> 0.5000000000 0.0000000000 0.0000000000 25 ! M
>>> 0.3333333333 0.3333333333 0.0000000000 40 ! K
>>> 0.0000000000 0.0000000000 0.0000000000 25 ! Gamma
>>> 0.0000000000 0.0000000000 0.5000000000 40 ! A
>>> 0.5000000000 0.0000000000 0.5000000000 25 ! L
>>> 0.3333333333 0.3333333333 0.5000000000 40 ! H
>>> 0.0000000000 0.0000000000 0.5000000000 1 ! A
>>>
>>>
>>> Best regards,
>>>
>>> --
>>>
>>> Iván Darío Arellano Ramírez
>>>
>>> Profesor Titular Programa de Ingeniería Física
>>>
>>> Director Grupo de Investigación en Modelado y Simulación
>>> Computacional
>>>
>>> Universidad Tecnológica de Pereira
>>>
>>>
>>> El contenido de este mensaje y sus anexos son únicamente
>>> para el uso del destinatario y pueden contener información
>>> clasificada o reservada. Si usted no es el destinatario
>>> intencional, absténgase de cualquier uso, difusión,
>>> distribución o copia de esta comunicación.
>>>
>>> _______________________________________________________________________________
>>> The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare.
>>> --------------------------------------------------------------------------------
>>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu <http://www.max-centre.eu>)
>>> users mailing listusers at lists.quantum-espresso.org
>>> https://lists.quantum-espresso.org/mailman/listinfo/users
>> --
>> Dr. Lorenzo Paulatto
>> IR IMPMC - CNRS UMR 7590 / Sorbonne Université / MNHN
>> phone: +33 (0)1 442 79822 / telegram: lpaulatto
>> http://www.impmc.upmc.fr/~paulatto/ -
>> https://anharmonic.github.io/
>> 23-24/423 B115, 4 place Jussieu 75252 Paris CX 05
>> _______________________________________________________________________________
>> The Quantum ESPRESSO Foundation stands in solidarity with all
>> civilians worldwide who are victims of terrorism, military
>> aggression, and indiscriminate warfare.
>> --------------------------------------------------------------------------------
>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu
>> <http://www.max-centre.eu>)
>> users mailing list users at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
>>
>>
>>
>> --
>>
>> Iván Darío Arellano Ramírez
>>
>> Profesor Titular Programa de Ingeniería Física
>>
>> Director Grupo de Investigación en Modelado y Simulación
>> Computacional
>>
>> Universidad Tecnológica de Pereira
>>
>>
>> El contenido de este mensaje y sus anexos son únicamente para el
>> uso del destinatario y pueden contener información clasificada o
>> reservada. Si usted no es el destinatario intencional, absténgase
>> de cualquier uso, difusión, distribución o copia de esta
>> comunicación.
>>
>> _______________________________________________________________________________
>> The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare.
>> --------------------------------------------------------------------------------
>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu <http://www.max-centre.eu>)
>> users mailing listusers at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
> --
> Dr. Lorenzo Paulatto
> IR IMPMC - CNRS UMR 7590 / Sorbonne Université / MNHN
> phone: +33 (0)1 442 79822 / telegram: lpaulatto
> http://www.impmc.upmc.fr/~paulatto/ - https://anharmonic.github.io/
> 23-24/423 B115, 4 place Jussieu 75252 Paris CX 05
> _______________________________________________________________________________
> The Quantum ESPRESSO Foundation stands in solidarity with all
> civilians worldwide who are victims of terrorism, military
> aggression, and indiscriminate warfare.
> --------------------------------------------------------------------------------
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu
> <http://www.max-centre.eu>)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
>
>
>
> --
>
> Iván Darío Arellano Ramírez
>
> Profesor Titular Programa de Ingeniería Física
>
> Director Grupo de Investigación en Modelado y Simulación Computacional
>
> Universidad Tecnológica de Pereira
>
>
> El contenido de este mensaje y sus anexos son únicamente para el uso
> del destinatario y pueden contener información clasificada o
> reservada. Si usted no es el destinatario intencional, absténgase de
> cualquier uso, difusión, distribución o copia de esta comunicación.
>
> _______________________________________________________________________________
> The Quantum ESPRESSO Foundation stands in solidarity with all civilians worldwide who are victims of terrorism, military aggression, and indiscriminate warfare.
> --------------------------------------------------------------------------------
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing listusers at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
--
Dr. Lorenzo Paulatto
IR IMPMC - CNRS UMR 7590 / Sorbonne Université / MNHN
phone: +33 (0)1 442 79822 / telegram: lpaulatto
http://www.impmc.upmc.fr/~paulatto/ - https://anharmonic.github.io/
23-24/423 B115, 4 place Jussieu 75252 Paris CX 05
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20250611/c0348fc8/attachment.html>
More information about the users
mailing list