[DFTB-Plus-User] R: R: negf calculation

[Alessandro Pecchia]

Hi,

 

I think you are using an old version of the manual or I really have to look at it (!)

The definition of the Transport block is outdated.

 

You should move FermiLevel in each contact block as well as Potential (one per contact).

The energy range must be specified in the block 

Analysis{ 

   TunnelingAndDos{ …here… } 

}

 

What version of the code are you using? 

You could download and test the beta version from github:

 

https://github.com/aradi/dftbplus

 

there is a parallel-negf branch we are currently merging for a forthcoming official release. 

We are happy if you can test it and report problems. 

 

 

Alessandro

 

 

 

 

Task = UploadContacts {

    FirstLayerAtoms =  1   61   121   181   241   301   361   421   481   541 

    FermiLevel [eV] = SetForAll { -3.112636 }

    ContactPotentials {

      source = 0.0

      drain [eV] = 0.0

    }

    EnergyRange [eV] = -6.0  -1.0

    EnergyStep [eV] = 0.02 

  }

}

 

Again many thanks for your help!

                            

Regards

 

Theodoros                                                                                                                                                                       

 

 

---- Original Message ----
From: "alessandro.pecchia" <alessandro.pecchia at ismn.cnr.it>
To: "User list for DFTB+ related questions" <dftb-plus-user at mailman.zfn.uni-bremen.de>
Sent: Wed, Apr 25, 2018, 11:38 PM
Subject: [DFTB-Plus-User] R: negf calculation

Hi,

 

 If I interpret correctly the problem is that the Geometry{} block has been removed in newest versions, so please remove it from your input. The parser expects Device in the Transport block.

Thanks for signaling this problem.

 

Regards,

 

Alessandro

 

 

 

 

Inviato dal mio dispositivo Samsung



-------- Messaggio originale --------
Da: Theodoros Leontiou <eng.lt at frederick.ac.cy> 
Data: 25/04/18 8:05 PM (GMT+01:00) 
A: dftb-plus-user at mailman.zfn.uni-bremen.de 
Oggetto: [DFTB-Plus-User] negf calculation 

Dear dftb+ specialist

 

I am trying to do my first dftb+ negf calculation.

However, I get an error I don't know how to resolve. 

 

I am running a test using the input files provided for the Silicon nanowire 

example. When I try to calculate the contact hamiltonian I get the

following:

 

ERROR!

-> Missing child: Device

Path: dftb_in/Transport

Line: 6-23 (File: dftb_in.hsd)

 

What is the meaning of the above error message?

 

I am grateful for your help

 

Regards

 

Theodoros

 

ps: I am attaching my input file below

 

 

####### BEGINNING OF INPUT FILE ##########################

Geometry = GenFormat {

<<< 'SiNW.gen'

}

 

 

Transport {

  Geometry {

    Device {

     AtomRange = 1 600

    }

    Contact {

      Id = "source"

      AtomRange = 601 720

    }

    Contact {

      Id = "drain"

      AtomRange = 721 840

    }

  }

  Task = ContactHamiltonian{

  ContactId = "source"

  }

}

 

 

Driver = {}

 

Hamiltonian = DFTB {

  SCC = Yes

  SCCTolerance = 1e-7

  MaxSCCIterations = 20

  MaxAngularMomentum = {

    Si ="p"

    H = "s"

  }

 

  Filling = Fermi {

    Temperature [Kelvin] = 0

  }

 

  SlaterKosterFiles = Type2FileNames{

    Prefix = "/home/leontiou/Dropbox/research/tight_binding/dftb+/dftb+mpi-negf.r4732/examples/SiNW/"

    Separator = "-"

    Suffix = ".skf"

  }

 

  KpointsAndWeights = SupercellFolding{

    8 0 0

    0 1 0

    0 0 1

    0.50 0.0 0.0

  }

 

Electrostatics = GammaFunctional {}

Eigensolver = DivideAndConquer{}

 

 

}

 

################ END OF INPUT FILE ##########################

 

 

 

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