I am trying to finish the lead example in your recent workshop 2018 for resistivity calculation.
I had finished the same example before from your EPW/Documentation site.
I am sorry that I have gotten few questions and I am really appreciate your answers.
Q1. In your workshop tutorial it is said that automatically lead.res.01 is created along with lead.a2f.01 files. However according to EPW/Documentation we have to run a python script to generate resistivity data. Is this a new feature of a new version or what ? If so wich EPW/Quantum Espresso modules I need to use?
Q2
Also I noted there is no separate location for k-mesh path (meshes/path.dat) given in epw.in. How the code get k-mesh path now?
Q3
I also have a question on what you have said about "n" in Zemans formula. Does this mean any typical metallic material contribute only 8 electron for mobility ?
For my real case I am interested about uranium compounds. Electron configuration of U-metal is [Rn] 5f3 6d1 7s2. How I should get this now.
Also if it is a compound ( U3Si) What it should be.
[color=#FFFF00:3oy6679a]where n is the number of electron per unit volume and n(!; T) is the Bose-Einstein distribution.
Usually this means the number of electrons that contribute to the mobility and so it is typically 8
(full shell) but not always. This number of electron is hardcoded in EPW/src/a2f.f90 along with
the temperature range (0-1000K). If you want to modify this, you will need to recompile the code.[/color:3oy6679a]
Q4
Also all the calculations are now running in the same folder (cannot see pp,phonons, epw folders). Is this also a new version?
I am sorry may be I am not updated, I am actually running QE 6.1 module. Please let me know what is the latest module we have now.
Keep in mind that this might be unstable. If you want a stable version you will have to wait the next release (a few months from now).
The calculation of the resistivity can be done with the python script or is now produced by EPW (this will be v5 in the next release).
Regarding the "n". It is indeed the number of electron that contributes to the mobility and vary with your system. You can read the book from Ziman called "Electrons and Phonons" that talks about that.
I actually didn’t get that chance. Thus I was waiting for information on the workshop and now following them for better understanding of calculation of electron relaxation time and resistivity which needs for my PhD project. But still I am not yet very sure how to do this.
I have already calculated linewidth.elself file and analysed to get Im(self). Also resistivity have been calculated with the python script and a2f_tr.01. I apreciate it very much if i can send those files to you or any other developer personaly and get comments on it.
I have no way to proceed without clarifying about this.
If you have trouble computing the resistivity, I suggest your try with the latest development version since it is inside the code and does not require you to change a python script by hand (except the thing about the n).
Thank you for providing me the link. I downloaded and compiled it and now trying the lead example.
I am having a problem to get the output from epw.in file.
I have finished scf.in, ph.in (pp.py to create and save required files) and nscf.in. But epw.in crashes and gives the following error.
Actually I ran the job correctly with epw.x. However I couldn’t avoid this error.
But when I remove parallel_k and parallel_q it works and I could reproduce what you have given in the tutorial. I am not sure why parallel_k and q does not work. I am trying this with QE 6.2.2(downloaded from github).
I got another problem with Wed5/exercise2/si.
epw2.in gave me the error below. (I copied only the error part of the epw2.out file). Can you please let me know how to solve this. I think I should mention that I copied fc.si file manually to the save folder (renamed as ifc.q2r) since the pp.py did not do that. Hope the error doesn’t have any effect with that.
Fermi Surface thickness = 1.200000 eV
This is computed with respect to the fine Fermi level 8.544315 eV
Only states between 7.344315 eV and 9.744315 eV will be included
Progression iq (fine) = 50/ 8000
Progression iq (fine) = 100/ 8000
Progression iq (fine) = 150/ 8000
Progression iq (fine) = 200/ 8000
Progression iq (fine) = 250/ 8000
Progression iq (fine) = 300/ 8000
Progression iq (fine) = 350/ 8000
Progression iq (fine) = 400/ 8000
Progression iq (fine) = 450/ 8000
Progression iq (fine) = 500/ 8000
Creation of a restart point
===================================================================
Temp [K] Fermi [eV] Hole density [cm^-3] Hole mobility [cm^2/Vs]
===================================================================
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Error in routine rdiagh (2):
diagonalization (DSYEV) failed
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
stopping ...
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Error in routine rdiagh (2):
diagonalization (DSYEV) failed
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
The reason I said that was because in your output it was written " [b:p48x8pts]PWscf[/b:p48x8pts] started at: Mon May 7 20:25:52 CST 2018
forrtl: severe (24): end-of-file during read, unit 5, file /proc/8616/fd/0"
Indeed those two variables have been removed as written in the log changes for the upcoming EPW 5: http://epw.org.uk/Main/About (toward the end).
Denationalization errors happen when your scattering rate is very small and therefore the mobility is super large. This is because you might not have enough k or q-points that contributes.
One way to fix this is to increase the restart frequency to 4000 for example. In that way, the code will only try to print the mobility after 4000 q-points.
You might need more k/q to have no zero scattering.
You can look at the values in the scattering output files.
I got the similar result in the exercise of Wed5/exercise2/si (mobility) with QE v.6.2.2 but I still have two questions.
In epw1.in, can I use the denser fine k/q grids instead of setting filkf (filqf) = ‘./LGX.txt’ since the band structure is not that important.
In epw2.in, the fine q points grid was assumed but you still set filkf = ‘./kpt.txt’. So similarly, can I also use the fine k points grid (for example, nkf1 = 10, nkf2 = 10, nkf3 = 10)? Actually I did this, but the result seems weird. The calculation was successfully done but the mobility was rathar large. I also checked the output file of scattering rate and most of the imaginary parts are zero.
I wanted to see the Im/Re and to get wannier functions in the same Si example. So I added write_wfn=.true. and wdata(12) = ‘wannier_plot= true’ . Now the epw1.in input is as copied below. However I am getting a strange problem now, when epw1.in is running it creates only up to UNK00014.1, but it gives me an error for UNK00015.1 and the job crashes ( forrtl: severe (24): end-of-file during read, unit 11, file /home/EPW-2018-WS/exercise2/4-si/UNK00015.1)
If I am correct, according to my input I should have 100 UNK files because LGX.txt has 100 points. I am confused why this creates only 14 files?
I tried another calculation to get Im/Re and wannier functions with QE 6.2.2. But similar issue arrives. Can this be a bug in QE 6.2.2?
To be honest, I never used the
write_wfn=.true. functionality of EPW. From looking at the code it seems it is only calling Wannier90 routines and could be outdated.
In any case, I would suggest you to use directly Wannier90 (without using EPW) if you want to get UNKXXX files.
i have met the same problem in SERTA calculation in pola material mobilibty calculation(not included in offical tuotrial GaN-II but calcualtion in yourprb article : Hole mobility of strained GaN from first principles)
my questions are:
1)when doing SERTA calculation in GaN-II,should i seperately calculate h&e mobility?
2)when “Error in routine rdiagh (2):diagonalization (DSYEV) failed” problem happens,
should i change fermi level or fsthick to invlove more states in calculation ?
will it help? I find maybe some wrong parameter for fermi_energy & fsthick may cause “We only need to compute 0 q-points in epwoutput”
and epw just finish itself or cause error
3)and what does “restart_step” you mentioned above increasing to 2000 do in mobility calculation?
will increase restart_step help?