Pb with spin orbit calculation

[username]

I am attempting to perform the calculation of Tc in Pb with spin orbit coupling using EPW v.4.1.0. Below is my input file for epw:

--
&inputepw
prefix = 'pb'
amass(1) = 207.2
outdir = './'

elph = .true.
kmaps = .false.
epbwrite = .true.
epbread = .false.

epwwrite = .true.
epwread = .false.

nbndsub = 8
nbndskip = 10

wannierize = .true.
num_iter = 300
dis_win_max = 21
dis_win_min = -3
dis_froz_min= -3
dis_froz_max= 13.5
proj(1) = 'Pb:sp3'

iverbosity = 0

elecselfen = .false.
phonselfen = .true.

parallel_k = .true.
parallel_q = .false.

fsthick = 6 ! eV
eptemp = 0.075 ! K
degaussw = 0.05 ! eV

a2f = .true.


dvscf_dir = './save'

nkf1 = 20
nkf2 = 20
nkf3 = 20

nqf1 = 20
nqf2 = 20
nqf3 = 20

nk1 = 6
nk2 = 6
nk3 = 6

nq1 = 6
nq2 = 6
nq3 = 6
/
16 cartesian
0.000000000000 0.000000000000 0.000000000000 0.0092593
-0.166666666667 0.166666666667 -0.166666666667 0.0740741
-0.333333333333 0.333333333333 -0.333333333333 0.0740741
0.500000000000 -0.500000000000 0.500000000000 0.0370370
0.000000000000 0.333333333333 0.000000000000 0.0555556
-0.166666666667 0.500000000000 -0.166666666667 0.2222222
0.666666666667 -0.333333333333 0.666666666667 0.2222222
0.500000000000 -0.166666666667 0.500000000000 0.2222222
0.333333333333 0.000000000000 0.333333333333 0.1111111
0.000000000000 0.666666666667 0.000000000000 0.0555556
0.833333333333 -0.166666666667 0.833333333333 0.2222222
0.666666666667 0.000000000000 0.666666666667 0.1111111
0.000000000000 -1.000000000000 0.000000000000 0.0277778
0.666666666667 -0.333333333333 1.000000000000 0.2222222
0.500000000000 -0.166666666667 0.833333333333 0.2222222
-0.333333333333 -1.000000000000 0.000000000000 0.1111111

With this input file, I obtain an error in the epw.out file of:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Error in routine read_dyn_mat_param (1):
error opening the dyn mat file
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

I have confirmed that the save directory contains the pb.dyn_q files.

Would you have any suggestions for how to fix this? Thank you for your assistance.

[sponce]

Hello,

If the calculation is with SOC, then the code is expecting to read the dyn files in XML format (inside the file folder).

You can use the python pp script to copy those with the correct name from the SOC example of EPW

Best,

Samuel

[username]

The pp.py script in the SOC examples does not copy any XML format files. Where would the correct dyn files be found and to what should they be renamed?

[sponce]

One example can be found in

qe-6.0/EPW/tests/Inputs/t04/pp.py

You can see that this script copy .xml files. Those will be generated if you do a phonon calculation from a SOC scf calculation.

[username]

This has resolved the issue. Thank you.

When I change the value of nqf1, nqf2, nqf3, epw stops running with:

Dipole matrix elements calculated


Calculating kmap and kgmap
Progress kmap: ########################################
Progress kgmap: ########################################
kmaps : 26.07s CPU 26.29s WALL ( 1 calls)
Symmetries of bravais lattice: 48
Symmetries of crystal: 48

How should this be solved?

[sponce]

Do you get any error message?

There should be no reasons. Maybe post the working and non-working input files?

Best,

Samuel

[username]

I am attempting to converge the calculation of Tc for Pb following the EPW papers. When I increase the phonon smearing with degaussq, here set to 50 meV, the values of lambda become large (2.55575) and the values of Tc too small (0.045222 K). Do you have any suggestions. Thank you.


--
&inputepw
prefix = 'pb'
amass(1) = 207.2
outdir = './'

elph = .true.
kmaps = .false.
epbwrite = .true.
epbread = .false.

epwwrite = .true.
epwread = .false.

nbndsub = 8
nbndskip = 10

wannierize = .true.
num_iter = 300
dis_win_max = 21
dis_win_min = -3
dis_froz_min= -3
dis_froz_max= 13.5
proj(1) = 'Pb:sp3'

iverbosity = 0

elecselfen = .false.
phonselfen = .true.

parallel_k = .true.
parallel_q = .false.

fsthick = 6 ! eV
eptemp = 0.075 ! K
degaussw = 0.05 ! eV
degaussq = 50.00

a2f = .true.

dvscf_dir = './save'

nkf1 = 30
nkf2 = 30
nkf3 = 30

nqf1 = 30
nqf2 = 30
nqf3 = 30

nk1 = 6
nk2 = 6
nk3 = 6

nq1 = 6
nq2 = 6
nq3 = 6
/
16 cartesian
0.000000000000 0.000000000000 0.000000000000 0.0092593
-0.166666666667 0.166666666667 -0.166666666667 0.0740741
-0.333333333333 0.333333333333 -0.333333333333 0.0740741
0.500000000000 -0.500000000000 0.500000000000 0.0370370
0.000000000000 0.333333333333 0.000000000000 0.0555556
-0.166666666667 0.500000000000 -0.166666666667 0.2222222
0.666666666667 -0.333333333333 0.666666666667 0.2222222
0.500000000000 -0.166666666667 0.500000000000 0.2222222
0.333333333333 0.000000000000 0.333333333333 0.1111111
0.000000000000 0.666666666667 0.000000000000 0.0555556
0.833333333333 -0.166666666667 0.833333333333 0.2222222
0.666666666667 0.000000000000 0.666666666667 0.1111111
0.000000000000 -1.000000000000 0.000000000000 0.0277778
0.666666666667 -0.333333333333 1.000000000000 0.2222222
0.500000000000 -0.166666666667 0.833333333333 0.2222222
-0.333333333333 -1.000000000000 0.000000000000 0.1111111

[sponce]

Hello,

This is a very large value. Note that the default value is 0.05 meV ...
For degaussw it is large but possible. Not for degaussq.

Best,

Samuel

[username]

Then I am a bit confused about the documentation. What parameter should I change to produce something along the lines of Table II in 'Electron-phonon interaction using Wannier functions'?

[carla.verdi]

Hi,
the values of smearing in that table correspond to the parameter 'degaussw' (in units of eV in the input), which relates to the broadening of the delta functions in eq, (4) of the paper. 'degaussq' instead corresponds to the broadening of the delta function in eq. (7) and you should set it to 0.5 (the units for it are meV).