Yambo Community Forum

Dear all,
I knew GW on top of DFT+U is not implemented, while I can do BSE directly on top of DFT+U+SOC by modifying in interfaces/p2y/mod_p2y.F as : if(pw_lda_plus_u) call warning(' LDA+U. Hubbard correction is not considered in yambo.') My system is a two-dimensional magnetic system, it is a metal without adding U, and a semiconductor with only 0.03eV gap after adding U. In my calculation, the role of SOC is considered. My DFT input is as follows:



/
&system
input_dft = 'pbe',
noncolin = .true.,
lspinorb = .true.,
ibrav = 0,
nat= 7,
ntyp= 3,
force_symmorphic=.true.
ecutwfc = 60,
! ecutrho = 600
occupations='smearing', smearing='gaussian', degauss=0.001,
!! nspin=2,
starting_magnetization(1)= 1
! nosym = .TRUE.
! noinv=.true.
! nosym_evc = .true.
lda_plus_u=.true.
lda_plus_u_kind=1
Hubbard_U(1)= 4.0

After performing the Yambo, The r_setup, which identifies the system as metal. I wonder if this is normal? Does it properly consider the correction of U values? Will it affect my next BSE calculation? Thank you~

[02.05] Energies & Occupations
==============================

[X] === General ===
[X] Electronic Temperature : 0.258606E-1 300.100 [eV K]
[X] Bosonic Temperature : 0.258606E-1 300.100 [eV K]
[X] Finite Temperature mode : yes
[X] El. density : 0.33349E+24 [cm-3]
[X] Fermi Level : 5.362300 [eV]

[X] === Gaps and Widths ===
[X] Conduction Band Min : 5.362300 [eV]
[X] Valence Band Max : 5.362300 [eV]
[X] Filled Bands : 108
[X] Metallic Bands : 109 111
[X] Empty Bands : 112 512

[X] === Metallic Characters ===
[X] N of el / N of met el : 109.0000 1.0031
[X] Average metallic occ. : 0.167181

[WARNING][X] Metallic system

Dear Shan,
probably because the small bandgap of your system Yambo set it as a metal. Nevertheless, for the BSE, as the occupations are read (and I guess that are 1.0 for the valence electrons and 0.0 for conduction electrons), the results shouldn't be affected by this.
Cheers,
Alejandro.

Dear Shan,
you can try to rerun the setup setting ElecTemp=0 eV

Best,
Daniele

Dear Daniele：
I have a question here. Do you suggest not to perform smaring in pwscf, or do you just need to manually set the electronic temperature to 0 during BSE calculation?
For example, change the Electronic Temperature: 0.258606E-1 300.100 [eV K」to zero.The order of doing this is limited. Set the setup for yambo, and then generate the file for yambo - X s Change the Electronic Temperature in the in file. Is that so?
In this case, my question is that although the broadening is very small, the ground state actually input to yambo through pwscf should be the ground state including temperature, right?
Best wishes!
Quxiao
BIT

Dear Quxiao,

my suggestion is to set:
"ElectTemp=0 eV" in the yambo setup input file: (yambo -i -V all).
and see if the system is seen as semiconductor: see the section " Energies & Occupations" in the r_setup.
Before doing this, remove all the pre-existing ndb* file in the SAVE directory.

If this is the case, then you can do all the following calculation maintaining the keyword "ElecTemp= 0 eV" in all the input files.

In case it does not work, you can also to run nscf calculation removing the smearing.

In this case, my question is that although the broadening is very small, the ground state actually input to yambo through pwscf should be the ground state including temperature, right?

Please note that the smearing it is not a "physical" temperature but a methodology to smear the occupation in case of metals or narrow band gap material.

Best,
Daniele