I want to calculate electron phonon interaction in Silicon regime and I make the following preparations as the yambo-py codes suggest:
1) scf calculation on a shifted 8*8*8 kgrid (scf.in)
2) nscf calculation on an unshifted 4*4*4 kgrid (nscf_4x4x4.in) using the save from step 1
3) use p2y to generate a SAVE file from step 2 to generate 20 random qpoints and substitute the first one with gamma point for the phonon calculation (ypp -k r -F kgrid.in)
4) use the save in step 2 (coarse grid) to calculate a elph matrix(02ph.in) on the qpoints in step 3
5) nscf calculation on an unshifted 8*8*8 kgrid (nscf_8x8x8.in) using the save from step 1
6) use the save in step 5 (dense grid) and elph matrix in step 4 to calculate the energy on the 20 random qpoints (04elph.in)
7) compile the s.dbph_0000* from elph_dir and SAVE generated from step 5 (dense grid) together to a new folder for further calculation
then I initialize the database and get the following results:
First, I use yambo_ph -i -V kpt -F yambo.in to generate the input and manually append MinusQ to the file as follow:
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setup # [R INI] Initialization
% IkSigLim
1 | 29 | # [KPT] QP K-points indices range
%
IkXLim= 29 # [KPT] X grid last k-point index
#BSEscatt # [KPT] Compute extended k/q scatering
MinusQ
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<---> [01] CPU structure, Files & I/O Directories
<---> [02] CORE Variables Setup
<---> [02.01] Unit cells
<---> [02.02] Symmetries
<---> [02.03] RL shells
<---> Shells finder |########################################| [100%] --(E) --(X)
<---> [02.04] K-grid lattice
<---> Grid dimensions : 8 8 8
<---> [02.05] Energies [ev] & Occupations
<---> [03] Transferred momenta grid
<---> [RL indx] Q-grid:Electron-Phonon databases
<---> [RL indx] Q BZ pts are /= from X grid BS pts. Gamma point only.
<---> [04] Timing Overview
<---> [05] Game Over & Game summary
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gkkp # [R] Electron-Phonon databases
DBsPATH= "." # Path to the PW el-ph databases
PHfreqF= "none" # PWscf format file containing the phonon frequencies
PHmodeF= "none" # PWscf format file containing the phonon modes
#GkkpExpand # Expand the gkkp in the whole BZ
#GkkpConvert # Convert the gkkp to new I/O format
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<---> [01] CPU structure, Files & I/O Directories
<---> [02] Y(ambo) P(ost)/(re) P(rocessor)
<---> [03] Core DB
<---> :: Electrons : 8.000000
<---> :: Temperature [ev]: 0.000000
<---> :: Lattice factors [a.u.]: 5.091500 5.091500 5.091500
<---> :: K points : 29
<---> :: Bands : 50
<---> :: Symmetries : 48
<---> :: RL vectors : 2085
<---> [04] K-point grid
<---> :: Q-points (IBZ): 1
<---> :: X K-points (IBZ): 29
<---> [05] CORE Variables Setup
<---> [05.01] Unit cells
<---> [05.02] Symmetries
<---> [05.03] RL shells
<---> [05.04] K-grid lattice
<---> Grid dimensions : 8 8 8
<---> [05.05] Energies [ev] & Occupations
<---> [06] == Electron-Phonon Interface: PW->Yambo Databases ==
<---> PW(ELPH) databases ...[PHONON] ...found 20 NOT Q-grid compatible
<58s> ELPH databases (WRITE) |########################################| [100%] 58s(E) 58s(X)
<58s> :: Modes : 6
<58s> :: Bands range : 50
<58s> Databases Q-points PW-formatted
0.000000000 0.000000000 0.000000000 1
-0.152828380 -0.435727954 0.045498498 1
0.334549755 -0.009765699 -0.307347476 1
0.433034539 0.073082991 -0.131813496 1
0.215498969 0.171638772 0.350320786 1
0.187392876 -0.167791083 0.041487098 1
-0.020649195 -0.418981194 0.134727001 1
-0.144443765 -0.406561524 -0.099925995 1
-0.082937986 -0.278221965 0.101857394 1
-0.054322589 -0.211238682 -0.259933800 1
0.212642178 -0.187416583 0.234584585 1
-0.480074733 0.088339582 -0.141250789 1
-0.283740252 -0.046697296 -0.289366126 1
0.185389072 0.487134457 -0.068466999 1
-0.207159266 0.305032223 0.176419392 1
-0.182985485 0.001356000 0.194662094 1
-0.185574368 0.306555659 -0.153673396 1
-0.208446771 -0.026296096 0.118550502 1
0.183740675 -0.151414290 0.083759591 1
-0.491928846 -0.079484589 0.173904687 1
<58s> [07] Game Over & Game summary
All the above calculation was performed on Yambo 4.5.1 and QE 6.4.1
ps: I think it's much more proper to post this question on the electron phonon interaction subforum but I didn't find a new topic bottom there. So I can only post it here
Thanks,