Dear Sir
I am doing the g0w0 calculations on a 2D semiconducting materials, while I encountered a problem: the valence band maximum (VBM) of DFT is located on Gamma (0 0 0 ) point, but the gw corrected VBM is at 0.000000 0.208333 0.000000. I am wondering why yambo change the location of VBM? The g0w0 input is as follows:
#
# __ __ _ __ __ ____ U ___ u
# \ \ / / U /"\ U u " \/ " u U  __") u \/"_ \/
# \ V / \/ _ \/ \ \/ / \ _ \/    
# U_"_u / ___ \      _)  .,_ _ 
# _ /_/ \_\ _ _ ____/ \_)\___/
# .,//(_ \\ >> <<,,,. _ \\_ \\
# \_) (__) (__) (__) (./ \.) (__) (__) (__)
#
#
# GPL Version 4.1.4 Revision 76
# MPI+OpenMP Build
# http://www.yambocode.org
#
gw0 # [R GW] GoWo Quasiparticle energy levels
ppa # [R Xp] Plasmon Pole Approximation
rim_cut # [R RIM CUT] Coulomb potential
HF_and_locXC # [R XX] HartreeFock Selfenergy and Vxc
em1d # [R Xd] Dynamical Inverse Dielectric Matrix
X_Threads= 16 # [OPENMP/X] Number of threads for response functions
DIP_Threads= 16 # [OPENMP/X] Number of threads for dipoles
SE_Threads= 16 # [OPENMP/GW] Number of threads for selfenergy
RandQpts=3000000
RandGvec= 100 RL # [RIM] Coulomb interaction RS components
CUTGeo= "box z" # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere X/Y/Z/XY..
% CUTBox
0.00  0.00  65.00  # [CUT] [au] Box sides
%
CUTRadius= 0.000000 # [CUT] [au] Sphere/Cylinder radius
CUTCylLen= 0.000000 # [CUT] [au] Cylinder length
EXXRLvcs= 10503 RL # [XX] Exchange RL components
Chimod= "Hartree" # [X] IP/Hartree/ALDA/LRC/BSfxc
% BndsRnXp
1  300  # [Xp] Polarization function bands
%
NGsBlkXp= 6 Ry # RL # [Xp] Response block size
% LongDrXp
1.000000  0.000000  0.000000  # [Xp] [cc] Electric Field
%
PPAPntXp= 27.21138 eV # [Xp] PPA imaginary energy
% GbndRnge
1  300  # [GW] G[W] bands range
%
GDamping= 0.10000 eV # [GW] G[W] damping
dScStep= 0.10000 eV # [GW] Energy step to evaluate Z factors
DysSolver= "n" # [GW] Dyson Equation solver ("n","s","g")
%QPkrange # [GW] QP generalized Kpoint/Band indices
1 61 3546
%
I attached the r_* log file for anyone to help me to analyze the problem? Thanks a lot
gw change the kpoint of VBM in 2D semiconductor
Moderators: Davide Sangalli, Daniele Varsano, andrea.ferretti, andrea marini, myrta gruning

 Posts: 75
 Joined: Fri May 03, 2013 10:20 am
gw change the kpoint of VBM in 2D semiconductor
You do not have the required permissions to view the files attached to this post.
Dr. Zhou LiuJiang
Fujian Institute of Research on the Structure of Matter
Chinese Academy of Sciences
Fuzhou, Fujian, 350002
Fujian Institute of Research on the Structure of Matter
Chinese Academy of Sciences
Fuzhou, Fujian, 350002
 Daniele Varsano
 Posts: 2319
 Joined: Tue Mar 17, 2009 2:23 pm
 Contact:
Re: gw change the kpoint of VBM in 2D semiconductor
Dear Dr. Zhou LiuJiang,
you may want to check your convergences, anyway from your report I can see you have QP energies
E= 0.07 at gamma
E= 0.12 at k=0.000000 0.208333 0.000000
so ~0.2 eV below than the energy at gamma point, i.e very similar to the energy difference you find at KS level (0.22eV).
Best,
Daniele
you may want to check your convergences, anyway from your report I can see you have QP energies
E= 0.07 at gamma
E= 0.12 at k=0.000000 0.208333 0.000000
so ~0.2 eV below than the energy at gamma point, i.e very similar to the energy difference you find at KS level (0.22eV).
Best,
Daniele
Dr. Daniele Varsano
S3CNR Institute of Nanoscience and MaX Center, Italy
MaX  Materials design at the Exascale
http://www.nano.cnr.it
http://www.maxcentre.eu/
S3CNR Institute of Nanoscience and MaX Center, Italy
MaX  Materials design at the Exascale
http://www.nano.cnr.it
http://www.maxcentre.eu/

 Posts: 75
 Joined: Fri May 03, 2013 10:20 am
Re: gw change the kpoint of VBM in 2D semiconductor
Dear Daniele,Daniele Varsano wrote:Dear Dr. Zhou LiuJiang,
E= 0.12 at k=0.000000 0.208333 0.000000
so ~0.2 eV below than the energy at gamma point, i.e very similar to the energy difference you find at KS level (0.22eV).
Daniele
How do you get the QP energy of 0.12 at k=0.000000 0.208333 0.000000? Actually, the VBM QP energies is 0.09701 eV at the 40th band, sixth kpoint (0.000000 0.208333 0.000000). The QP energy difference is about 0.03 eV eV, while that at KS level is up to 0.22 eV, showing a significant distinction. Can you tell me which parameter usually determine the inconsistency? Thanks a lot
Dr. Zhou LiuJiang
Fujian Institute of Research on the Structure of Matter
Chinese Academy of Sciences
Fuzhou, Fujian, 350002
Fujian Institute of Research on the Structure of Matter
Chinese Academy of Sciences
Fuzhou, Fujian, 350002
 Daniele Varsano
 Posts: 2319
 Joined: Tue Mar 17, 2009 2:23 pm
 Contact:
Re: gw change the kpoint of VBM in 2D semiconductor
Dear Zhou LiuJiang,
according to the report you posted:
QP [eV] @ K [6] (iku): 0.000000 0.208333 0.000000
B=35 Eo= 0.98 E= 1.13 EEo= 0.15 Re(Z)=0.77 Im(Z)=.2555E2 nlXC=16.13 lXC=13.91 So= 2.036
B=36 Eo= 0.93 E= 1.08 EEo= 0.15 Re(Z)=0.77 Im(Z)=.2450E2 nlXC=16.21 lXC=14.00 So= 2.025
B=37 Eo= 0.85 E= 1.08 EEo= 0.23 Re(Z)=0.78 Im(Z)=.1807E2 nlXC=16.10 lXC=13.91 So= 1.897
B=38 Eo= 0.78 E= 1.00 EEo= 0.22 Re(Z)=0.78 Im(Z)=.1731E2 nlXC=16.23 lXC=14.05 So= 1.906
B=39 Eo= 0.23 E= 0.13 EEo= 0.10 Re(Z)=0.77 Im(Z)=.2436E2 nlXC=16.31 lXC=14.77 So= 1.664
B=40 Eo= 0.22 E= 0.12 EEo= 0.10 Re(Z)=0.77 Im(Z)=.2422E2 nlXC=16.32 lXC=14.78 So= 1.665
I can see at Band 40:
EKS=0.22eV
EQP=0.12eV
Are we looking at the same file?
Best,
Daniele
according to the report you posted:
QP [eV] @ K [6] (iku): 0.000000 0.208333 0.000000
B=35 Eo= 0.98 E= 1.13 EEo= 0.15 Re(Z)=0.77 Im(Z)=.2555E2 nlXC=16.13 lXC=13.91 So= 2.036
B=36 Eo= 0.93 E= 1.08 EEo= 0.15 Re(Z)=0.77 Im(Z)=.2450E2 nlXC=16.21 lXC=14.00 So= 2.025
B=37 Eo= 0.85 E= 1.08 EEo= 0.23 Re(Z)=0.78 Im(Z)=.1807E2 nlXC=16.10 lXC=13.91 So= 1.897
B=38 Eo= 0.78 E= 1.00 EEo= 0.22 Re(Z)=0.78 Im(Z)=.1731E2 nlXC=16.23 lXC=14.05 So= 1.906
B=39 Eo= 0.23 E= 0.13 EEo= 0.10 Re(Z)=0.77 Im(Z)=.2436E2 nlXC=16.31 lXC=14.77 So= 1.664
B=40 Eo= 0.22 E= 0.12 EEo= 0.10 Re(Z)=0.77 Im(Z)=.2422E2 nlXC=16.32 lXC=14.78 So= 1.665
I can see at Band 40:
EKS=0.22eV
EQP=0.12eV
Are we looking at the same file?
Best,
Daniele
Dr. Daniele Varsano
S3CNR Institute of Nanoscience and MaX Center, Italy
MaX  Materials design at the Exascale
http://www.nano.cnr.it
http://www.maxcentre.eu/
S3CNR Institute of Nanoscience and MaX Center, Italy
MaX  Materials design at the Exascale
http://www.nano.cnr.it
http://www.maxcentre.eu/