[DFTB-Plus-User] NEGF_MPI: rare DOS results

[NACIR M. TIT]

Hi Matias,

I agree with Marton. Your results look just fine. DOS is constant at Fermi level for a range of about 1.5 eV. This must be CNT-AC (armchair). Even Fermi level is about -4.6 which is about the Work Function of graphene.
You should feel confident with what you obtain. Good Luck!

Nacir

**********************************
Dr. Nacir Tit
Professor of Computational Physics
Physics Department
UAE University
Al-Ain
United Arab Emirates
Tel: +971 3 7136 326
Fax: +971 3 7671 291
Email: ntit at uaeu.ac.ae<mailto:ntit at uaeu.ac.ae>
**********************************
________________________________
From: dftb-plus-user-bounces at mailman.zfn.uni-bremen.de [dftb-plus-user-bounces at mailman.zfn.uni-bremen.de] on behalf of matias berdakin [matiasberdakin at gmail.com]
Sent: Friday, November 06, 2015 7:18 PM
To: dftb-plus-user at mailman.zfn.uni-bremen.de
Subject: Re: [DFTB-Plus-User] NEGF_MPI: rare DOS results

sorry I forgot to say bye in the last mail

Thanks in advance
Matias Berdakin

2015-11-06 10:18 GMT-03:00 matias berdakin <matiasberdakin at gmail.com<mailto:matiasberdakin at gmail.com>>:
Hi everybody

I'm doing my firsts trials with the DFTB+_NEGF_MPI (after the Tutorial examples). I'm computing the DOS and the transmission function (non scc) of a conducting carbon nanotube. At  first glance, the overall feature of the DOS is what is expected for this system (see attached figure). Nevertheless  the result present a series of symmetric spikes that make no sense.
I can not find the error in the calculation. So an idea is welcome.
At the end of the message I have pasted the geometry and the dftb_in.hsd files.
[Imágenes integradas 1]
Geometry = GenFormat {
<<< 'coords_grande.gen'
}

Transport {
  Device {
    AtomRange = 1 240
    FirstLayerAtoms =  1 121
  }
  Contact {
    Id = "source"
    AtomRange = 241 480
    FermiLevel [eV] = -4.602
    potential [eV] = 0.0
  }
  Contact {
    Id = "drain"
    AtomRange = 481 720
    FermiLevel [eV] = -4.602
    potential [eV] = 0.0
  }
}

Hamiltonian = DFTB {
  SCC = No
  MaxAngularMomentum = {
    C = "p"
  }

  SlaterKosterFiles = Type2FileNames {
    Prefix = "/mio-1-1/"

    Separator = "-"
    Suffix = ".skf"
  }

Eigensolver = GreensFunction {
ContourPoints = 50 50
}

Analysis = {
    TunnelingAndDos {
      Verbosity = 101
      EnergyRange [eV] = -7.0 -3.0
      EnergyStep [eV] = 0.005
      Region = {
        Atoms = 1 240
      }
    }
}



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