El-Ph for spin-polarized and noncollinear systems

Deals with issues related to computation of optical spectra, solving the Bethe-Salpeter equation.

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luonn
Posts: 13
Joined: Mon Nov 12, 2018 4:52 pm

El-Ph for spin-polarized and noncollinear systems

Post by luonn » Mon Mar 18, 2019 5:01 am

Dear Yambo Developer and Yambo users,

I found some problems in calculating the electron-phonon couplings (qe6.1 and yambo4.2.1).
A. Generate the input files.
1). When the SOC is included, use the uniform grid method is ok. But, use the random q-point method, there is a problem when generating the ndb.elph_gkkp* files, list in the below (test Si):
yambo_ph:

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_|      _|   _|_|   _|      _|  _|_|_|     _|_|
  _|  _|   _|    _| _|_|  _|_| _|    _| _|    _|
    _|     _|_|_|_| _|  _|  _| _|_|_|   _|    _|
    _|     _|    _| _|      _| _|    _| _|    _|
    _|     _|    _| _|      _| _|_|_|     _|_|



 <---> [01] CPU structure, Files & I/O Directories
 <---> [02] CORE Variables Setup
 <---> [02.01] Unit cells
 <---> [02.02] Symmetries
 <---> [WARNING]Spatial Inversion not found among the given symmetry list
 <---> [02.03] RL shells
 <03s> [02.04] K-grid lattice
 <03s> [02.05] Energies [ev] & Occupations
 <03s> [03] Transferred momenta grid
 <03s> [RL indx] Q-grid:Electron-Phonon databases
 <03s> [RL indx] Q BZ pts are /= from X grid BS pts. Gamma point only.
  [[b]get stuck here[/b]]
The r_setup file shows: 
[03] Transferred momenta grid
 =============================

 [RL indx] Q-grid:Electron-Phonon databases

 IBZ Q-points : 10
 BZ  Q-points :  53

 Q [00001] : -0.08695  -0.16663  -0.44824 (iku) * weight   0.01887
 Q [00002] :-0.132335 -0.347009  0.448239 (iku) * weight   0.07547
 Q [00003] : 0.166216  0.444148  0.000000 (iku) * weight   0.07547
 Q [00004] :  0.05307  -1.18674   0.00000 (iku) * weight  0.150943
 Q [00005] : -0.08695  -0.39558  -0.89648 (iku) * weight   0.07547
 Q [00006] : 0.166216  0.395579  0.000000 (iku) * weight   0.07547
 Q [00007] :-0.132335  1.186736  0.896477 (iku) * weight  0.150943
 Q [00008] : 0.166629 -0.395579 -0.347009 (iku) * weight   0.07547
 Q [00009] : 0.395579 -1.186736 -0.448239 (iku) * weight  0.150943
 Q [00010] :-0.448239  0.448239 -0.448239 (iku) * weight  0.150943
  
 Q [00001] : -0.10609  -0.20329  -0.54687 (cc ) * weight   0.01887
 Q [00002] :-0.161453 -0.423364  0.546867 (cc ) * weight   0.07547
 Q [00003] : 0.202790  0.541877  0.000000 (cc ) * weight   0.07547
 Q [00004] :  0.06475  -1.44786   0.00000 (cc ) * weight  0.150943
 Q [00005] : -0.10609  -0.48262  -1.09373 (cc ) * weight   0.07547
 Q [00006] : 0.202790  0.482620  0.000000 (cc ) * weight   0.07547
 Q [00007] :-0.161453  1.447860  1.093734 (cc ) * weight  0.150943
 Q [00008] : 0.203293 -0.482620 -0.423364 (cc ) * weight   0.07547
 Q [00009] : 0.482620 -1.447860 -0.546867 (cc ) * weight  0.150943
 Q [00010] :-0.546867  0.546867 -0.546867 (cc ) * weight  0.150943
 [RL indx] Q BZ pts are /= from X grid BS pts. Gamma point only.
2) For spin-polarized calculations, both the uniform and the random q-point methods have the following problem:
ypp_ph:

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 ___ __  _____  __ __  _____   _____
|   Y  ||  _  ||  Y  ||  _  \ |  _  |
|   |  ||. |  ||.    ||. |  / |. |  |
 \_  _/ |. _  ||.\_/ ||. _  \ |. |  |
  |: |  |: |  ||: |  ||: |   \|: |  |
  |::|  |:.|:.||:.|:.||::.   /|::.  |
  `--"  `-- --"`-- --"`-----" `-----"


 <---> [01] CPU structure, Files & I/O Directories
 <---> [02] Y(ambo) P(ost)/(re) P(rocessor)
 <---> [03] Core DB
 <---> :: Electrons             : 8.000000
 <---> :: Temperature       [ev]:0.9500E-3
 <---> :: Lattice factors [a.u.]: 5.150000  5.150000  5.150000
 <---> :: K points              : 3
 <---> :: Bands                 : 30
 <---> :: Symmetries            :  48
 <---> :: RL vectors            :  5985
 <---> [04] K-point grid
 <---> :: Q-points   (IBZ): 3
 <---> :: X K-points (IBZ): 3
 <---> [05] CORE Variables Setup
 <---> [05.01] Unit cells
 <---> [05.02] Symmetries
 <---> [05.03] RL shells
 <---> [05.04] K-grid lattice
 <---> [05.05] Energies [ev] & Occupations
 <---> [06] == Electron-Phonon Interface: PW->Yambo Databases ==
 <---> PW(ELPH) databases ...[PHONON] ...incorrect K-point correspondance
 <---> [07] Game Over
I have found that someone has asked the same question in the forum (viewtopic.php?f=15&t=1349), has it been fixed?

B. Does the gaussian smearing method in pwscf work for el-ph calculations in yambo?
I find that use gaussian smearing in pwscf for spin nonpolarized calculations (Si) indeed can successfully generate the input files for yambo, but, when I attemp to reproduce the results in yambo tutorials, there is a problem (yambo4.1):
02_OMS.in:

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#                                                           
# :::   :::   :::     ::::    ::::  :::::::::   ::::::::    
# :+:   :+: :+: :+:   +:+:+: :+:+:+ :+:    :+: :+:    :+:   
#  +:+ +:+ +:+   +:+  +:+ +:+:+ +:+ +:+    +:+ +:+    +:+   
#   +#++: +#++:++#++: +#+  +:+  +#+ +#++:++#+  +#+    +:+   
#    +#+  +#+     +#+ +#+       +#+ +#+    +#+ +#+    +#+   
#    #+#  #+#     #+# #+#       #+# #+#    #+# #+#    #+#   
#    ###  ###     ### ###       ### #########   ########    
#                                                           
#                                                           
#              GPL Version 4.1.4 Revision 76                
#                    MPI+OpenMP Build                       
#                http://www.yambo-code.org                  
#
gw0                          # [R GW] GoWo Quasiparticle energy levels
el_ph_corr                   # [R] Electron-Phonon Correlation
SE_Threads=  40              # [OPENMP/GW] Number of threads for self-energy
DysSolver= "n"               # [GW] Dyson Equation solver ("n","s","g")
GphBRnge=  8                 # [ELPH] G[W] bands range
FANdEtresh=0.1000E-5   eV    # [ELPH] Energy treshold for Fan denominator
DWdEtresh=0.1000E-5    eV    # [ELPH] Energy treshold for DW denominator
% ElPhModes
  1 |  6 |                   # [ELPH] Phonon modes included
%
GDamping=  0.10000     eV    # [GW] G[W] damping
dScStep=  0.10000      eV    # [GW] Energy step to evaluate Z factors
ExtendOut                   # [GW] Print all variables in the output file
RandQpts=100000                   # [RIM] Number of random q-points in the BZ
WRgFsq                      # [ELPH] Dump on file gFsq coefficients
#NewtDchk                    # [GW] Test dSc/dw convergence
OnMassShell                 # [F GW] On mass shell approximation
%QPkrange                    # [GW] QP generalized Kpoint/Band indices
  1|  3|  1| 30|
%
%QPerange                    # [GW] QP generalized Kpoint/Energy indices
  1|  3| 0.0|-1.0|
%
o-02.qp

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#                                                           
# Y88b    /   e           e    e      888~~\    ,88~-_      
#  Y88b  /   d8b         d8b  d8b     888   |  d888   \     
#   Y88b/   /Y88b       d888bdY88b    888 _/  88888    |    
#    Y8Y   /  Y88b     / Y88Y Y888b   888  \  88888    |    
#     Y   /____Y88b   /   YY   Y888b  888   |  Y888   /     
#    /   /      Y88b /          Y888b 888__/    `88_-~      
#                                                           
#                                                           
#             GPL Version 4.1.4 Revision 76                 
#                    MPI+OpenMP Build                       
#               http://www.yambo-code.org                   
#
# GW [Newton Solver]
#
#  == El-Ph Self-Energy ==
#  [ph] dS/dw steps        : 2
#  [ph] dS/dw step     [ev]:  0.10000
#  [ph] Sc/G damping   [ev]:  0.10000
#  El-Ph correlation      : yes
#  El-Ph Sc. G bands      :  1  8
#  El-Ph phonon branches  :  1  6
#  El-Ph momenta used     : 3
#  Energy treshold   [FAN]:0.1000E-5
#  Energy treshold    [DW]:0.1000E-5
#  QP @ K 001 - 003 : b 001 - 030
#
#  K-point    Band       Eo         E          E-Eo       Z          Width[meV]
#
   1.00000    1.00000  -12.22806        NaN        NaN    1.00000        NaN
  1.000000   2.000000  -0.261952        NaN        NaN   1.000000        NaN
  1.000000   3.000000  -0.261952        NaN        NaN   1.000000        NaN
  1.000000   4.000000  -0.261952        NaN        NaN   1.000000        NaN
  1.000000   5.000000   2.154991        NaN        NaN   1.000000        NaN
  1.000000   6.000000   2.154991        NaN        NaN   1.000000        NaN
  1.000000   7.000000   2.154991        NaN        NaN   1.000000        NaN
  1.000000   8.000000   2.976995        NaN        NaN   1.000000        NaN
....
I do not know why the calculated qp energy and the width are wrong?

Could you please to give me any suggestions?
thank you very much

Best regards,

Nannan Luo
Nannan Luo
Low-Dimensional Materials and Devices Laboratory,
Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University
C2-7, iPark, Nanshan district, Shenzhen, Guangdong province, China 518055
Tel: (+86)18811369291
E-mail: luo-nn@sz.tsinghua.edu.cn

aseemrajan
Posts: 10
Joined: Mon Nov 18, 2019 11:44 am

Re: El-Ph for spin-polarized and noncollinear systems

Post by aseemrajan » Wed Oct 13, 2021 9:54 am

Dear Nannan,

Could you find a solution for generating ndb.elph_gkkp* files for the spin-polarized calculations with uniform grid?
I encountered the same error of "incorrect K-point correspondance".

Warm regards,
Aseem
Aseem Rajan Kshirsagar,
Postdoctoral researcher,
Department of Physics and Material Science,
University of Luxembourg (Limpertsberg campus)

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