Yambo Community Forum

Posted: **Tue Jan 06, 2026 2:04 pm**

Dear all,

I am working on a very small system consisting of three atoms (an indirect band gap material). I performed the PPA calculation at the k-point 68|68|17|18, where band 17 is the highest occupied band and bands 18–150 are unoccupied. Subsequently, I carried out the interpolation over the full Brillouin zone (k-points 1–74) for bands 6–25.

However, during the ypp calculation, I encounter the following error indicating that there are not enough states to converge the Fermi level.

Code: Select all

 <---> [01] MPI/OPENMP structure, Files & I/O Directories
 <---> MPI Cores-Threads   : 1(CPU)-128(threads)
 <---> [02] Y(ambo) P(ost)/(re) P(rocessor)
 <---> [03] Core DB
 <---> :: Electrons             : 34.00000
 <---> :: Temperature           : 0.950044E-3 [eV]
 <---> :: Lattice factors       :  6.95999   6.02755  41.76000 [a.u.]
 <---> :: K points              :  74
 <---> :: Bands                 : 150
 <---> :: Symmetries            : 2
 <---> :: RL vectors            : 201889
 <---> [04] K-point grid
 <---> :: Q-points   (IBZ):  74
 <---> :: X K-points (IBZ):  74
 <---> [05] CORE Variables Setup
 <---> [05.01] Unit cells
 <---> [05.02] Symmetries
 <---> [05.03] Reciprocal space
 <---> [05.04] K-grid lattice
 <---> Grid dimensions      :  12  12
 <---> [05.05] Energies & Occupations
 <---> [05.05.01] External/Internal QP corrections
 <---> E<./all_Bz/ndb.QP[ PPA@E  27.21138 * XG 243 * Xb 1-150 * Scb 1-150]
 <---> [dE_from_DB-Nearest K] Exact matches       :  100.0000 [o/o]
 <---> [WR./SAVE//ndb.QP_interpolated]-------------------------------------------------
 <--->  Lattice constants                                :   6.95999   6.02755  41.76000
 <--->  Coulomb cutoff potential                         : none
 <--->  Electronic Temperature                           :  300.2000 [K]
 <--->  Bosonic    Temperature                           :  300.1000 [K]
 <--->  Green`s function   energies                      : Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
 <--->  wavefunctions                                    : Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
 <--->  PPA    diel. fun.  energies                      : Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
 <--->  wavefunctions                                    : Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
 <--->  QP tot states                                    :  1480
 <--->  GF energies kind                                 : Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
 <--->  GF WF`s kind                                     : Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
 <--->  Xs energies kind                                 : Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
 <--->  Xs WF`s kind                                     : Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
 <---> - S/N 006760 ---------------------------------------------- v.05.03.00 r.23959 -
 <---> [QP_apply] Action to be applied: E<./all_Bz/ndb.QP[ PPA@E  27.21138 * XG 243 * Xb 1-150 * Scb 1-150]
 <---> [05.05.01.01]  QP corrections report

[ERROR] STOP signal received while in[05.05.01.01]  QP corrections report
[ERROR] Not enough states to converge the Fermi Level

I would appreciate any guidance on how to resolve this issue. The r_setup file and the other input files are attached.

Posted: **Wed Jan 07, 2026 8:38 am**

Dear Dhanjit,

most probably ypp get confused in applying the GW correction for just one k point, being all the other k point uncorrected.
If you want to interpolate along a path you should calculate the correction for the k points in your regular grid, i.e. considering all the k points available.

If you instead want to apply the calculated correction for one k point to all the band structure, you can interpolate the KS bands and apply a scissor operator according to your calculated QP value.

Best,
Daniele

Posted: **Wed Jan 07, 2026 10:26 am**

Dear Daniele,
Thank you very much for your reply and for the clarification.
Following your suggestion, I recalculated the GW corrections by considering all k points in the regular grid and restricted the QP window to 5 valence bands and 5 conduction bands. I then used the same band range consistently in the subsequent ypp step. However, I am still encountering the same error related to the Fermi-level convergence when applying the QP corrections.

Posted: **Thu Jan 08, 2026 5:58 am**

Dear Daniele,
I did the GW calculation at one k point and the interpolated it all over the BZ for 6 CB and 6 VB, but this time with occupation = fixed in QE (earlier i used mp, and mv) and its working now. It seems the issue is because of smearing technique.
For such a system how can one compute the GW structure providing electronic temperature to the system?

Posted: **Mon Jan 12, 2026 8:37 am**

Dear Dhanjit,

you can set an electronic temperature using the keyword ElecTemp in the yambo input file (independently to what has been used in QE), e.g. ElecTemp=300 K, but I suggest you to set it to zero e.g. (ElecTemp= 0.0 eV) if your system has not metallic character, i.e. in presence of a gap.
Best,

Daniele

Yambo Community Forum

Not enough states to converge the Fermi Level

Not enough states to converge the Fermi Level

Re: Not enough states to converge the Fermi Level

Re: Not enough states to converge the Fermi Level

Re: Not enough states to converge the Fermi Level

Re: Not enough states to converge the Fermi Level