The confusing of the results of DOS calculated by cp2k (density found at/around Fermi energy for insulator)

[Jannen]

Dear CP2K Users,

I am calculate the DOS for a crystal structure. It is a insulator. The density of state was found at Fermi energy level as shown in attached picture. I was really confused by the results. The DOS should be 0 at Fermi energy level. Even though the plots was broadening using deskinsgroup code, but that will just cause a slightly shifting above the Fermi energy level. Could anyone help me on the results? Any problem with the input? 

Please see the attached settings for DFT section.

  &DFT

    BASIS_SET_FILE_NAME BASIS_MOLOPT

    POTENTIAL_FILE_NAME GTH_POTENTIALS

    CHARGE 0

    MULTIPLICITY 1

    UKS TRUE

    &QS

      EPS_DEFAULT 1.0E-14

    &END QS

    &MGRID

      CUTOFF 400

      NGRIDS 4

      REL_CUTOFF 60

    &END MGRID

    &SCF

      SCF_GUESS RESTART

      EPS_SCF 1.0E-07

      MAX_SCF 1000

      &OT TRUE

       PRECONDITIONER FULL_ALL

       MINIMIZER CG

       ENERGY_GAP 0.001

     &END OT

      &PRINT

        &RESTART OFF

        &END RESTART

      &END PRINT

    &END SCF

    &XC

      &XC_FUNCTIONAL PBE

      &END XC_FUNCTIONAL

         &VDW_POTENTIAL

           DISPERSION_FUNCTIONAL PAIR_POTENTIAL

             &PAIR_POTENTIAL

              TYPE DFTD3

              REFERENCE_FUNCTIONAL PBE

              PARAMETER_FILE_NAME dftd3.dat

              R_CUTOFF 10.0

             &END PAIR_POTENTIAL

          &END VDW_POTENTIAL

    &END XC

    &PRINT

         &PDOS

            NLUMO -1

            COMPONENTS TRUE

            &LDOS

               COMPONENTS TRUE

               LIST  1..486    

            &END LDOS

         &END

     &END PRINT

  &END DFT

Best regards,

[Marcella Iannuzzi]

For insulators there is no definition of the Fermi energy. 

Your system shows a clear gap, indeed it is an insulator.

In your plot, the zero is most probably set at the energy of the highest occupied state.

But this choice is arbitrary.

Regards

Marcella

[Jannen]

Hi Marcella,

Thanks so much for the explanation. Yes, the zero is shifted to the highly occupied state. The state near Zero will become very small peaks if I use a smaller smearing width.  I was confused by Fermi energy and Fermi level. Fermi level is defined for insulator. 

Best,

Jannen