exciton binding energy
Moderators: Davide Sangalli, andrea marini, Daniele Varsano
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exciton binding energy
Hi Developers,
Would you please explain how we can estimate binding energy of exciton??
(Is it "bandgap - first exciton peak")
What is the difference between bright and dark exciton?
Best
S. Ataei, University of Tehran, Iran
Would you please explain how we can estimate binding energy of exciton??
(Is it "bandgap - first exciton peak")
What is the difference between bright and dark exciton?
Best
S. Ataei, University of Tehran, Iran
S. Ataei, PhD student at University of Tehran, Iran.
- Daniele Varsano
- Posts: 3848
- Joined: Tue Mar 17, 2009 2:23 pm
- Contact:
Re: exciton binding energy
Dear Smanaeh,
Binding of an exciton: QP band gap - excitation energy of the exciton you are interested in.
Bright -> finite oscillator strength (intensity)
Dark --> zero or very small intensity (so no optically active).
Best,
Daniele
Binding of an exciton: QP band gap - excitation energy of the exciton you are interested in.
Bright -> finite oscillator strength (intensity)
Dark --> zero or very small intensity (so no optically active).
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/
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/
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- Posts: 165
- Joined: Tue Jan 21, 2014 9:03 am
Re: exciton binding energy
Dear Daniele,
Thanks.
But if I want to compare exciton binding energy with PL peak
which excitation energy should be considered???
(Is it the first peak of imaginary part of the epsilon function??)
Best regards
Thanks.
But if I want to compare exciton binding energy with PL peak
which excitation energy should be considered???
(Is it the first peak of imaginary part of the epsilon function??)
Best regards
S. Ataei, PhD student at University of Tehran, Iran.
- Daniele Varsano
- Posts: 3848
- Joined: Tue Mar 17, 2009 2:23 pm
- Contact:
Re: exciton binding energy
Dear Samaneh,
PL can be very hard to describe, it really depends on the physics of your system if comparing with the first excitation is a good approximation or not.
Anyway, you can discuss it with your colleagues and collaborators, this is not a question strictly related with the code.
Best,
Daniele
PL can be very hard to describe, it really depends on the physics of your system if comparing with the first excitation is a good approximation or not.
Anyway, you can discuss it with your colleagues and collaborators, this is not a question strictly related with the code.
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/
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/
-
- Posts: 165
- Joined: Tue Jan 21, 2014 9:03 am
Re: exciton binding energy
Thanks a lot.
1- would you please explain what are the data in o.eel output file ???
2- There are a lot of data for constant dielectric function(w=0) in the output file(o.eps)
but according to the experimental data there is
just one value for it, how should we compare them??
Best regards
1- would you please explain what are the data in o.eel output file ???
2- There are a lot of data for constant dielectric function(w=0) in the output file(o.eps)
but according to the experimental data there is
just one value for it, how should we compare them??
Best regards
S. Ataei, PhD student at University of Tehran, Iran.
- Daniele Varsano
- Posts: 3848
- Joined: Tue Mar 17, 2009 2:23 pm
- Contact:
Re: exciton binding energy
It is the eels spectrum (electron energy loss), essentially 1/eps_M(w).1- would you please explain what are the data in o.eel output file ???
As you can see in the top of the file you have:2- There are a lot of data for constant dielectric function(w=0) in the output file(o.eps)
but according to the experimental data there is
just one value for it, how should we compare them??
Code: Select all
E/ev[1] eps /Im[2] eps /Re[3] eps0/Im[4] eps0/Re[5]
eps0 is the dielectric function calculated in the independent particle approximation.
So, this is not the static dielectric function, the static values is the one corresponding to E=0. The static dielectric constant is the real part.
All this info are explained in the tutorials.
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/
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/
-
- Posts: 165
- Joined: Tue Jan 21, 2014 9:03 am
Re: exciton binding energy
Dear Daniele,
Cartesian coordinates in ypp.in for hole position is
a.u. or angstrom??
Best
Cartesian coordinates in ypp.in for hole position is
a.u. or angstrom??
Best
S. Ataei, PhD student at University of Tehran, Iran.
-
- Posts: 165
- Joined: Tue Jan 21, 2014 9:03 am
Re: exciton binding energy
Dear daniele,
Does yambo -b mean the static dielectric with E=0???
Best
Does yambo -b mean the static dielectric with E=0???
Best
S. Ataei, PhD student at University of Tehran, Iran.
- Daniele Varsano
- Posts: 3848
- Joined: Tue Mar 17, 2009 2:23 pm
- Contact:
Re: exciton binding energy
Dear Smaneh,
simply typing yambo -H
you can see:
it is the static inverse dielectric matrix (w=0!). It is the entire matrix epsm1_q(G,G') to be used in a BSE calculation and *not* the macroscopic dielectric constant. You do not have any output.
Daniele
simply typing yambo -H
you can see:
Code: Select all
-h :Short Help
-H :Long Help
-J <opt> :Job string identifier
-V <opt> :Input file verbosity
[opt=RL,kpt,sc,qp,io,gen,resp,all]
-F <opt> :Input file
-I <opt> :Core I/O directory
-O <opt> :Additional I/O directory
-C <opt> :Communications I/O directory
-N :Skip MPI initialization
-D :DataBases properties
-S :DataBases fragmentation
-M :Memory distribution (parallel runs)
-i :Initialization
-o <opt> :Optics [opt=(c)hi is (G)-space / (b)se is (eh)-space ]
-k <opt> :Kernel [opt=hartree/alda/lrc/hf/sex]
(hf/sex only eh-space; lrc only G-space)
-y <opt> :BSE solver [opt=h/d/(p/f)i]
(h)aydock/(d)iagonalization/(i)nversion
-c :Coulomb interaction
-x :Hartree-Fock Self-energy and local XC
-d :Dynamical Inverse Dielectric Matrix
-b :Static Inverse Dielectric Matrix
-p <opt> :GW approximations [opt=(p)PA/(c)HOSEX]
-g <opt> :Dyson Equation solver
[opt=(n)ewton/(s)ecant/(g)reen]
-l :GoWo Quasiparticle lifetimes
-a :ACFDT Total Energy
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/
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/
-
- Posts: 165
- Joined: Tue Jan 21, 2014 9:03 am
Re: exciton binding energy
Thanks.
But how can I calculate the dielectric constant (E=0) with yambo code???
But how can I calculate the dielectric constant (E=0) with yambo code???
S. Ataei, PhD student at University of Tehran, Iran.