Solve the BSE equation at a finite temperature

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shan dong
Posts: 23
Joined: Thu Oct 17, 2019 5:26 am

Solve the BSE equation at a finite temperature

Dear all,
It is possible to calculate the relationship between the exciton excitation energy and the temperature under finite temperature conditions by using the yambo code?
Waiting for your replay. Thank you.
Shan Dong
PhD student
Beijing Institute of Technology,China

Daniele Varsano
Posts: 2723
Joined: Tue Mar 17, 2009 2:23 pm
Contact:

Re: Solve the BSE equation at a finite temperature

Dear Shan Dong,

it is not clear what you mean by "relationship between the exciton excitation energy and the temperature under finite temperature conditions", can you be more explicit about what you would like to calculate?

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

shan dong
Posts: 23
Joined: Thu Oct 17, 2019 5:26 am

Re: Solve the BSE equation at a finite temperature

Daniele Varsano wrote:
Sat Mar 13, 2021 5:25 pm
Dear Shan Dong,

it is not clear what you mean by "relationship between the exciton excitation energy and the temperature under finite temperature conditions", can you be more explicit about what you would like to calculate?

Best,
Daniele
Dear Daniele,
Thanks for your reply.I want to solve the BSE equation at different temperatures.
Best,
Shan Dong
PhD student
Beijing Institute of Technology,China

claudio
Posts: 320
Joined: Tue Mar 31, 2009 11:33 pm
Contact:

Re: Solve the BSE equation at a finite temperature

Dear Shan Dong,

it is possible to solve the BSE at finite temperature with Yambo, please have a look to these two tutorials

http://www.yambo-code.org/wiki/index.ph ... n_Coupling

http://www.yambo-code.org/wiki/index.ph ... emperature

Notice at present Yambo does different approximation in the BSE at finite temperature, that are described in the second tutorial.

Best
Claudio
Claudio Attaccalite
[CNRS/ Aix-Marseille Université/ CINaM laborarory / TSN department
Campus de Luminy – Case 913
13288 MARSEILLE Cedex 09
web site: http://www.attaccalite.com
Freely download scientific books from: http://www.freescience.info

shan dong
Posts: 23
Joined: Thu Oct 17, 2019 5:26 am

Re: Solve the BSE equation at a finite temperature

claudio wrote:
Mon Mar 15, 2021 11:40 am
Dear Shan Dong,

it is possible to solve the BSE at finite temperature with Yambo, please have a look to these two tutorials

http://www.yambo-code.org/wiki/index.ph ... n_Coupling

http://www.yambo-code.org/wiki/index.ph ... emperature

Notice at present Yambo does different approximation in the BSE at finite temperature, that are described in the second tutorial.

Best
Claudio
Dear Claudio,
Many thanks!
I do some G0W0 calculations with varying ElecTemp setting to check the the gap vs temperature.After that I do some BSE calculations with varying ElecTemp to check the electron–hole bonding vs temperature. In this process, I did not consider Electron Phonon Coupling, I don’t know if my calculation is correct.Here is my GW and BSE calculation at 200K temperature.

gw0 # [R GW] GoWo Quasiparticle energy levels
ppa # [R Xp] Plasmon Pole Approximation
HF_and_locXC # [R XX] Hartree-Fock Self-energy and Vxc
em1d # [R Xd] Dynamical Inverse Dielectric Matrix
StdoHash= 40 # [IO] Live-timing Hashes
Nelectro= 60.00000 # Electrons number
ElecTemp= 0.01724000 eV # Electronic Temperature
BoseTemp=-1.000000 eV # Bosonic Temperature
OccTresh=0.1000E-4 # Occupation treshold (metallic bands)
NLogCPUs=0 # [PARALLEL] Live-timing CPUs (0 for all)
DBsIOoff= "none" # [IO] Space-separated list of DB with NO I/O. DB=(DIP,X,HF,COLLs,J,GF,CARRIERs,OBS,W,SC,BS,ALL)
DBsFRAGpm= "none" # [IO] Space-separated list of +DB to FRAG and -DB to NOT FRAG. DB=(DIP,X,W,HF,COLLS,K,BS,QINDX,RT,ELP
FFTGvecs= 9055 RL # [FFT] Plane-waves
#WFbuffIO # [IO] Wave-functions buffered I/O
PAR_def_mode= "memory" # [PARALLEL] Default distribution mode ("balanced"/"memory"/"workload")
X_all_q_CPU= "1 1 32 1" # [PARALLEL] CPUs for each role
X_all_q_ROLEs= "q k c v" # [PARALLEL] CPUs roles (q,g,k,c,v)
X_all_q_nCPU_LinAlg_INV= 2 # [PARALLEL] CPUs for Linear Algebra
#SE_CPU= "" # [PARALLEL] CPUs for each role
#SE_ROLEs= "" # [PARALLEL] CPUs roles (q,qp,b)
EXXRLvcs= 50 Ry # [XX] Exchange RL components
VXCRLvcs= 50 Ry # [XC] XCpotential RL components
#UseNLCC # [XC] If present, add NLCC contributions to the charge density
Chimod= "HARTREE" # [X] IP/Hartree/ALDA/LRC/PF/BSfxc
ChiLinAlgMod= "LIN_SYS" # [X] inversion/lin_sys
XfnQPdb= "none" # [EXTQP Xd] Database
XfnQP_N= 1 # [EXTQP Xd] Interpolation neighbours
% XfnQP_E
0.000000 | 1.000000 | 1.000000 | # [EXTQP Xd] E parameters (c/v) eV|adim|adim
%
XfnQP_Z= ( 1.000000 , 0.000000 ) # [EXTQP Xd] Z factor (c/v)
XfnQP_Wv_E= 0.000000 eV # [EXTQP Xd] W Energy reference (valence)
% XfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (valence) eV| 1|eV^-1
%
XfnQP_Wv_dos= 0.000000 eV # [EXTQP Xd] W dos pre-factor (valence)
XfnQP_Wc_E= 0.000000 eV # [EXTQP Xd] W Energy reference (conduction)
% XfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (conduction) eV| 1 |eV^-1
%
XfnQP_Wc_dos= 0.000000 eV # [EXTQP Xd] W dos pre-factor (conduction)
ShiftedPaths= "" # [Xd] Shifted grids paths (separated by a space)
% QpntsRXp
1 | 7 | # [Xp] Transferred momenta
%
% BndsRnXp
1 | 150 | # [Xp] Polarization function bands
%
NGsBlkXp= 7 Ry # [Xp] Response block size
CGrdSpXp= 100.0000 # [Xp] [o/o] Coarse grid controller
% EhEngyXp
-1.000000 |-1.000000 | eV # [Xp] Electron-hole energy range
%
% LongDrXp
1.000000 | 0.000000 | 0.000000 | # [Xp] [cc] Electric Field
%
PPAPntXp= 27.21138 eV # [Xp] PPA imaginary energy
XTermKind= "none" # [X] X terminator ("none","BG" Bruneval-Gonze)
XTermEn= 40.00000 eV # [X] X terminator energy (only for kind="BG")
GfnQPdb= "none" # [EXTQP G] Database
GfnQP_N= 1 # [EXTQP G] Interpolation neighbours
% GfnQP_E
0.000000 | 1.000000 | 1.000000 | # [EXTQP G] E parameters (c/v) eV|adim|adim
%
GfnQP_Z= ( 1.000000 , 0.000000 ) # [EXTQP G] Z factor (c/v)
GfnQP_Wv_E= 0.000000 eV # [EXTQP G] W Energy reference (valence)
% GfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP G] W parameters (valence) eV| 1|eV^-1
%
GfnQP_Wv_dos= 0.000000 eV # [EXTQP G] W dos pre-factor (valence)
GfnQP_Wc_E= 0.000000 eV # [EXTQP G] W Energy reference (conduction)
% GfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP G] W parameters (conduction) eV| 1 |eV^-1
%
GfnQP_Wc_dos= 0.000000 eV # [EXTQP G] W dos pre-factor (conduction)
BoseCut= 0.10000 # [BOSE] Finite T Bose function cutoff
% GbndRnge
1 | 360 | # [GW] G[W] bands range
%
GDamping= 0.10000 eV # [GW] G[W] damping
dScStep= 0.10000 eV # [GW] Energy step to evaluate Z factors
GTermKind= "none" # [GW] GW terminator ("none","BG" Bruneval-Gonze)
GTermEn= 40.81708 eV # [GW] GW terminator energy (only for kind="BG")
DysSolver= "n" # [GW] Dyson Equation solver ("n","s","g")
#NewtDchk # [GW] Test dSc/dw convergence
#ExtendOut # [GW] Print all variables in the output file
#OnMassShell # [F GW] On mass shell approximation
%QPkrange # # [GW] QP generalized Kpoint/Band indices
1|7|50|70|
%
%QPerange # # [GW] QP generalized Kpoint/Energy indices
1|7| 0.000000|-1.000000|
%

em1s # [R Xs] Static Inverse Dielectric Matrix
rim_cut # [R RIM CUT] Coulomb potential
optics # [R OPT] Optics
bss # [R BSS] Bethe Salpeter Equation solver
bse # [R BSE] Bethe Salpeter Equation.
bsk # [R BSK] Bethe Salpeter Equation kernel
StdoHash= 40 # [IO] Live-timing Hashes
Nelectro= 60.00000 # Electrons number
ElecTemp= 0.01724000 eV # Electronic Temperature
BoseTemp=-1.000000 eV # Bosonic Temperature
OccTresh=0.1000E-4 # Occupation treshold (metallic bands)
NLogCPUs=0 # [PARALLEL] Live-timing CPUs (0 for all)
DBsIOoff= "none" # [IO] Space-separated list of DB with NO I/O. DB=(DIP,X,HF,COLLs,J,GF,CARRIERs,OBS,W,SC,BS,ALL)
DBsFRAGpm= "none" # [IO] Space-separated list of +DB to FRAG and -DB to NOT FRAG. DB=(DIP,X,W,HF,COLLS,K,BS,QINDX,RT,ELP
FFTGvecs= 50 Ry # [FFT] Plane-waves
#WFbuffIO # [IO] Wave-functions buffered I/O
PAR_def_mode= "memory" # [PARALLEL] Default distribution mode ("balanced"/"memory"/"workload")
X_all_q_CPU= "1 1 32 1" # [PARALLEL] CPUs for each role
X_all_q_ROLEs= "q k c v" # [PARALLEL] CPUs roles (q,g,k,c,v)
X_all_q_nCPU_LinAlg_INV= 2 # [PARALLEL] CPUs for Linear Algebra
#BS_CPU= "" # [PARALLEL] CPUs for each role
#BS_ROLEs= "" # [PARALLEL] CPUs roles (k,eh,t)
BS_nCPU_LinAlg_INV= 2 # [PARALLEL] CPUs for Linear Algebra
BS_nCPU_LinAlg_DIAGO= 2 # [PARALLEL] CPUs for Linear Algebra
NonPDirs= "none" # [X/BSS] Non periodic chartesian directions (X,Y,Z,XY...)
RandQpts= 2000000 # [RIM] Number of random q-points in the BZ
RandGvec= 1 RL # [RIM] Coulomb interaction RS components
#QpgFull # [F RIM] Coulomb interaction: Full matrix
% Em1Anys
0.00 | 0.00 | 0.00 | # [RIM] X Y Z Static Inverse dielectric matrix
%
IDEm1Ref=0 # [RIM] Dielectric matrix reference component 1(x)/2(y)/3(z)
CUTGeo= "box Z" # [CUT] Coulomb Cutoff geometry: box/cylinder/sphere/ws X/Y/Z/XY..
% CUTBox
0.00 | 0.00 | 36.00 | # [CUT] [au] Box sides
%
CUTRadius= 0.000000 # [CUT] [au] Sphere/Cylinder radius
CUTCylLen= 0.000000 # [CUT] [au] Cylinder length
CUTwsGvec= 0.700000 # [CUT] WS cutoff: number of G to be modified
#CUTCol_test # [CUT] Perform a cutoff test in R-space
Chimod= "HARTREE" # [X] IP/Hartree/ALDA/LRC/PF/BSfxc
ChiLinAlgMod= "LIN_SYS" # [X] inversion/lin_sys
BSEmod= "retarded" # [BSE] resonant/retarded/coupling
BSKmod= "SEX" # [BSE] IP/Hartree/HF/ALDA/SEX
BSSmod= "d" # [BSS] (h)aydock/(d)iagonalization/(i)nversion/(t)ddft
DbGdQsize= 1.000000 # [X,DbGd][o/o] Percentual of the total DbGd transitions to be used
BSENGexx= 50 Ry # [BSK] Exchange components
#ALLGexx # [BSS] Force the use use all RL vectors for the exchange part
BSENGBlk= 6 Ry # [BSK] Screened interaction block size
#WehDiag # [BSK] diagonal (G-space) the eh interaction
#WehCpl # [BSK] eh interaction included also in coupling
KfnQPdb= "E </home/ycli/home2/ds/scf/soc/661/200k-2/ndb.QP" # [EXTQP BSK BSS] Database
KfnQP_N= 1 # [EXTQP BSK BSS] Interpolation neighbours
% KfnQP_E
0.000000 | 1.000000 | 1.000000 | # [EXTQP BSK BSS] E parameters (c/v) eV|adim|adim
%
KfnQP_Z= ( 1.000000 , 0.000000 ) # [EXTQP BSK BSS] Z factor (c/v)
KfnQP_Wv_E= 0.000000 eV # [EXTQP BSK BSS] W Energy reference (valence)
% KfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP BSK BSS] W parameters (valence) eV| 1|eV^-1
%
KfnQP_Wv_dos= 0.000000 eV # [EXTQP BSK BSS] W dos pre-factor (valence)
KfnQP_Wc_E= 0.000000 eV # [EXTQP BSK BSS] W Energy reference (conduction)
% KfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP BSK BSS] W parameters (conduction) eV| 1 |eV^-1
%
KfnQP_Wc_dos= 0.000000 eV # [EXTQP BSK BSS] W dos pre-factor (conduction)
DipApproach= "G-space v" # [Xd] [G-space v/R-space x/Covariant/Shifted grids]
#DipPDirect # [Xd] Directly compute <v> also when using other approaches for dipoles
ShiftedPaths= "" # [Xd] Shifted grids paths (separated by a space)
Gauge= "length" # [BSE] Gauge (length|velocity)
#NoCondSumRule # [BSE] Do not impose the conductivity sum rule in velocity gauge
#MetDamp # [BSE] Define \w+=sqrt(\w*(\w+i\eta))
DrudeWBS= ( 0.00 , 0.00 ) eV # [BSE] Drude plasmon
#Reflectivity # [BSS] Compute reflectivity at normal incidence
BoseCut= 0.10000 # [BOSE] Finite T Bose function cutoff
% BEnRange
-1.00000 | 5.00000 | eV # [BSS] Energy range
%
% BDmRange
0.10000 | 0.10000 | eV # [BSS] Damping range
%
BEnSteps= 700 # [BSS] Energy steps
% BLongDir
1.000000 | 0.000000 | 0.000000 | # [BSS] [cc] Electric Field
%
% BSEBands
57 | 64 | # [BSK] Bands range
%
% BSEEhEny
-1.000000 |-1.000000 | eV # [BSK] Electron-hole energy range
%
WRbsWF # [BSS] Write to disk excitonic the WFs
#BSSPertWidth # [BSS] Include QPs lifetime in a perturbative way
XfnQPdb= "E </home/ycli/home2/ds/scf/soc/661/200k-2/ndb.QP" # [EXTQP Xd] Database
XfnQP_N= 1 # [EXTQP Xd] Interpolation neighbours
% XfnQP_E
0.000000 | 1.000000 | 1.000000 | # [EXTQP Xd] E parameters (c/v) eV|adim|adim
%
XfnQP_Z= ( 1.000000 , 0.000000 ) # [EXTQP Xd] Z factor (c/v)
XfnQP_Wv_E= 0.000000 eV # [EXTQP Xd] W Energy reference (valence)
% XfnQP_Wv
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (valence) eV| 1|eV^-1
%
XfnQP_Wv_dos= 0.000000 eV # [EXTQP Xd] W dos pre-factor (valence)
XfnQP_Wc_E= 0.000000 eV # [EXTQP Xd] W Energy reference (conduction)
% XfnQP_Wc
0.00 | 0.00 | 0.00 | # [EXTQP Xd] W parameters (conduction) eV| 1 |eV^-1
%
XfnQP_Wc_dos= 0.000000 eV # [EXTQP Xd] W dos pre-factor (conduction)
% QpntsRXs
1 | 164 | # [Xs] Transferred momenta
%
% BndsRnXs
1 | 150 | # [Xs] Polarization function bands
%
NGsBlkXs= 6 Ry # [Xs] Response block size
GrFnTpXs= "T" # [Xs] Greens function (T)ordered,(R)etarded,(r)senant,(a)ntiresonant [T, R, r, Ta, Ra]
% DmRngeXs
0.10000 | 0.10000 | eV # [Xs] Damping range
%
CGrdSpXs= 100.0000 # [Xs] [o/o] Coarse grid controller
% EhEngyXs
-1.000000 |-1.000000 | eV # [Xs] Electron-hole energy range
%
% LongDrXs
1.000000 | 0.000000 | 0.000000 | # [Xs] [cc] Electric Field
%
DrudeWXs= ( 0.00 , 0.00 ) eV # [Xs] Drude plasmon
XTermKind= "none" # [X] X terminator ("none","BG" Bruneval-Gonze)
XTermEn= 40.00000 eV # [X] X terminator energy (only for kind="BG")
Shan Dong
PhD student
Beijing Institute of Technology,China

Daniele Varsano
Posts: 2723
Joined: Tue Mar 17, 2009 2:23 pm
Contact:

Re: Solve the BSE equation at a finite temperature

Dear Shan,

in this way you are only changing the occupation number according to a Fermi Dirac distribution.
Note that if your system is a semiconductor this does not have any effect on QP energies and spectra.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/