I encountered a problem when I used EPW to calculate the electro-acoustic coupling strength. The output file will output a Fermi level after the epw.x calculation, but the Fermi level in Self consistent calculation is quite different from the epw.x output.

The Self-consistent output (fermi level):

the epw. X output (fermi level):the Fermi energy is 2.9974 ev

In the recent calculation of another system, the Fermi energy level difference between Wannier fitting and self-consistent output was 1.0eV, which made the calculation of a2F inaccurate, so the following test was carried out. The following two tests were carried out using the system corresponding to the previous calculation of Fermi energy levels. However, the results of a2F vary greatly. May I ask whether my test here is useful? Can the EPw.x calculation of a2F be calculated by specifying Fermi levels in the input file?DOS = 1.280437 states/spin/eV/Unit Cell at Ef= 3.000886 eV

Here are the input files for the two tests (the calculated input files for PW.x are the same) :

test1:

input file of epw.x

output **.a2f.01&inputepw

outdir = './outdir/'

ep_coupling = .true.

elph = .true.

kmaps = .false.

epwwrite = .true.

epwread = .false.

wannierize = .true.

! num_iter = 0

dis_froz_min= 2.0

dis_froz_max= 4.0

proj(1) = 'Mo:l=1;l=2'

wdata(1) = 'Begin Kpoint_Path'

wdata(2) = 'G 0.00 0.00 0.00 M 0.00 0.50 0.00'

wdata(3) = 'M 0.00 0.50 0.00 K 0.333 0.333 0.00'

wdata(4) = 'K 0.333 0.333 0.0 G 0.00 0.00 0.00'

wdata(5) = 'End Kpoint_Path'

wdata(6) = 'bands_plot = .true.'

wdata(7) = 'bands_num_points = 55'

wdata(8) = 'guiding_centres = .true.'

wdata(9) = 'dis_num_iter = 5000'

bands_skipped = 'exclude_bands = 1:12'

system_2d=.true.

etf_mem = 1

nbndsub = 16 ! Lowest boundary for the phonon frequency

ephwrite = .false. ! Writes .ephmat files used when Eliasberg = .true.

fsthick = 0.1 ! eV

degaussw = 0.01 ! eV

nsmear = 1

nqsmear = 1

delta_smear = 0.01 ! eV

degaussq = 0.5 ! meV

nqstep = 500

! eliashberg = .true.

! laniso = .true.

! limag = .true.

! lpade = .true.

conv_thr_iaxis = 1.0d-4

! max_memlt = 3.0d0

! asr_typ = 'crystal'

delta_approx = .true.,

! elecselfen = .true.,

phonselfen = .true.,

a2f = .true. ,

wscut = 1.0 ! eV Upper limit over frequency integration/summation in the Elisashberg eq

! nstemp = 12 ! Nr. of temps

! temps = 2.00 13.00 ! K provide list of temperetures OR (nstemp and temps = tempsmin tempsmax for even space mode)

nsiter = 500

muc = 0.20876

dvscf_dir = '../phonon/save'

nk1 = 12

nk2 = 12

nk3 = 1

nq1 = 6

nq2 = 6

nq3 = 1

! mp_mesh_k = .true.

nkf1 = 120

nkf2 = 120

nkf3 = 1

nqf1 = 60

nqf2 = 60

nqf3 = 1

/

test2:87.2111998 0.0000000

87.3863227 0.0000000

87.5614456 0.0000000

Integrated el-ph coupling

# 0.6672296

Phonon smearing (meV)

# 0.5000000

Electron smearing (eV) 0.0100000

Fermi window (eV) 0.1000000

Summed el-ph coupling 0.6604335

input file of epw.x

output **.a2f.01&inputepw

outdir = './outdir/'

ep_coupling = .true.

elph = .true.

kmaps = .false.

epwwrite = .true.

epwread = .false.

wannierize = .true.

! num_iter = 0

dis_froz_min= 2.0

dis_froz_max= 4.0

proj(1) = 'Mo:l=1;l=2'

wdata(1) = 'Begin Kpoint_Path'

wdata(2) = 'G 0.00 0.00 0.00 M 0.00 0.50 0.00'

wdata(3) = 'M 0.00 0.50 0.00 K 0.333 0.333 0.00'

wdata(4) = 'K 0.333 0.333 0.0 G 0.00 0.00 0.00'

wdata(5) = 'End Kpoint_Path'

wdata(6) = 'bands_plot = .true.'

wdata(7) = 'bands_num_points = 55'

wdata(8) = 'guiding_centres = .true.'

wdata(9) = 'dis_num_iter = 5000'

bands_skipped = 'exclude_bands = 1:6'

system_2d=.true.

etf_mem = 1

nbndsub = 16 ! Lowest boundary for the phonon frequency

ephwrite = .false. ! Writes .ephmat files used when Eliasberg = .true.

fsthick = 0.1 ! eV

degaussw = 0.01 ! eV

nsmear = 1

nqsmear = 1

delta_smear = 0.01 ! eV

degaussq = 0.5 ! meV

nqstep = 500

efermi_read = .true.

fermi_energy = 3.000886

! eliashberg = .true.

! laniso = .true.

! limag = .true.

! lpade = .true.

conv_thr_iaxis = 1.0d-4

! max_memlt = 3.0d0

! asr_typ = 'crystal'

delta_approx = .true.,

! elecselfen = .true.,

phonselfen = .true.,

a2f = .true. ,

wscut = 1.0 ! eV Upper limit over frequency integration/summation in the Elisashberg eq

! nstemp = 12 ! Nr. of temps

! temps = 2.00 13.00 ! K provide list of temperetures OR (nstemp and temps = tempsmin tempsmax for even space mode)

nsiter = 500

muc = 0.20876

dvscf_dir = '../../../phonon/save'

nk1 = 12

nk2 = 12

nk3 = 1

nq1 = 6

nq2 = 6

nq3 = 1

! mp_mesh_k = .true.

nkf1 = 120

nkf2 = 120

nkf3 = 1

nqf1 = 60

nqf2 = 60

nqf3 = 1

/

87.2111998 0.0000000

87.3863227 0.0000000

87.5614456 0.0000000

Integrated el-ph coupling

# 0.7338264

Phonon smearing (meV)

# 0.5000000

Electron smearing (eV) 0.0100000

Fermi window (eV) 0.1000000

Summed el-ph coupling 0.7271920

In addition, I would like to ask you a question: after wannier fitting is well calculated, how to adjust the Fermi energy level output of EPw. x to be inconsistent with the self-consistent output? Thank you