[DFTB-Plus-User] Different Fermi energy calculated by DFTB+NEGF and only DFTB+

[Enlong Liu]

Dear all,

I am doing transport calculation to boron nanotubes (BNT). But I find out
that there is a huge difference in fermi energy in different cases.

In the transport calculation, I used DFTB+NEGF to calculate the contact
firstly, which is part of BNT at one end and the result is -10eV
approximately. But if I just calculate the DOS or band structure to the
same BNT part, the fermi energy is just -4eV. It is interesting since I
think all other parameters are the same, only the calculation situation is
different, one is just DFTB+ for DOS, the other includes NEGF to calculate
contact properties before doing transport calculation.

I tried some other system like Si or Ag. There is the same problem, fermi
energy difference in common calculation and transport calculation. Could
any one help me with that?

Thanks a lot!

Best regards,
Enlong

-- 
Faculty of Engineering at K.U. Leuven
BIOTECH at TU Dresden
Email: liuenlong20 at gmail.com; enlong.liu at student.kuleuven.be;
enlong.liu at biotech.tu-dresden.de
Mobile Phone: +4917666191322
Mailing Address: Zi. 0108R, Budapester Straße 24, 01069, Dresden, Germany
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.dftb-plus.info/pipermail/dftb-plus-user/attachments/20140508/49cb35b3/attachment.html>