[DFTB-Plus-User] Regarding Fermi energy

u3129004 at edu.gifu-u.ac.jp u3129004 at edu.gifu-u.ac.jp
Wed Jan 20 05:34:44 CET 2016


Dear Dr.Gabriele,

Thank you very much for your teaching.

Many thanks,
Kazuma
----- Original Message -----
> Hi Kazuma,
> 
> the technique used by DFTB+ to calculate the Fermi level has been
> already touched in the mailing list
> 
> https://mailman.zfn.uni-bremen.de/pipermail/dftb-plus-user/2011/000684.html

> 
> Short story, I can't see from your transmission but I would guess the
> Fermi level is close to a band edge. At 0K you can compensate the
> deficiency described in the link above by setting it in the middle of
> the gap, and as it is also described in the SCC section of this online
> tutorial
> http://www.dftb-plus.info/fileadmin/DFTB-Plus/public/tutorials/cecamhp/html/transport.html

> 
> 
> Best,
> Gabriele
> 
> 
> On 01/19/2016 05:23 PM, u3129004 at edu.gifu-u.ac.jp wrote:
> > Dear Dr. Gabriele,
> > 
> > Thank you very much for your early reply. After calculation of 
contacts, 
> > I found that Fermi energy is -3.777471. 
> > 
> > So in this case, is the Fermi energy -3.777471?
> > 
> > However if the Fermi energy is -3.777471, it follows that this 
material 
> > is not semiconductor.
> > 
> > Sincerely yours,
> > Kazuma
> > 
> > 
> > ----- Original Message -----
> >> Dear Kazuma,
> >>
> >> in the transport calculation the Fermi level is not defined, 
because 
> > the
> >> system is not necessarily in equilibrium. The value 0.0 is just a
> >> placeholder.
> >>
> >> In fact, you set yourself the Fermi level of the leads as input 
> > quantity
> >> in dtb_in.hsd.device.
> >>
> >>
> >> On 01/19/2016 05:05 PM, u3129004 at edu.gifu-u.ac.jp wrote:
> >>> Dear DFTB+ users,
> >>>
> >>> I calculated graphene nanoribbon using DFTB+NEGF (please refer to 
an 
> >>> attached file). I checkd the position of Fermi energy by typing 
like 
> >>> following:
> >>>
> >>> grep "Fermi energy" ./detailed.out
> >>>
> >>> However it was found that Fermi energy = 0.0 eV.
> >>> I think this value is not true because in this case of graphene, 
> > this 
> >>> material should be semiconductor. 
> >>>
> >>> Please tell me how to know right Fermi energy.
> >>>
> >>> In addition, this is the first time I use DFTB+NEGF. So it is 
> > possible 
> >>> that I made mistakes in my input files. It would be very helpful 
if 
> > you 
> >>> could give me any advice.
> >>>
> >>> Thank you in advance,
> >>> Kazuma
> >>> ---------------------------------------------------
> >>> Kazuma KIHIRA
> >>> Environmental & Renewable Energy Systems Division
> >>> Graduate School of Engineering, Gifu University
> >>> E-mail:u3129004 at edu.gifu-u.ac.jp
> >>> ---------------------------------------------------
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> DFTB-Plus-User mailing list
> >>> DFTB-Plus-User at mailman.zfn.uni-bremen.de
> >>> https://mailman.zfn.uni-bremen.de/cgi-bin/mailman/listinfo/dftb-plus-user

> > 
> >>>
> >>
> >> -- 
> >> --
> >> Dr. Gabriele Penazzi
> >> BCCMS - University of Bremen
> >>
> >> http://www.bccms.uni-bremen.de/
> >> http://sites.google.com/site/gabrielepenazzi/
> >> phone: +49 (0) 421 218 62337
> >> mobile: +49 (0) 151 19650383
> >> _______________________________________________
> >> DFTB-Plus-User mailing list
> >> DFTB-Plus-User at mailman.zfn.uni-bremen.de
> >> https://mailman.zfn.uni-bremen.de/cgi-bin/mailman/listinfo/dftb-plus-user

> > 
> >>
> > 
> > 
> > _______________________________________________
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> > DFTB-Plus-User at mailman.zfn.uni-bremen.de
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> > 
> 
> -- 
> --
> Dr. Gabriele Penazzi
> BCCMS - University of Bremen
> 
> http://www.bccms.uni-bremen.de/
> http://sites.google.com/site/gabrielepenazzi/
> phone: +49 (0) 421 218 62337
> mobile: +49 (0) 151 19650383
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> 




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