[Wannier] transport in wannier90

[nicolas poilvert]

Dear Y.P. Wang,

The Wannier code as it stands right now is capable
of computing "bulk" Quantum Conductance automatically.
"bulk" means that your system must be periodic (like a pristine
carbon nanotube or a pristine nanowire for example).
As for a "Lead Conductor Lead" calculation (denoted 'lcr' in
the Wannier input file) you need to give 5 matrices to the code
in order to compute the Quantum Conductance. The five matrices
are :

  H_L     that you should call <seedname>_htL.dat, where seedname
              is the same as your master <seedname>.win file.
              This matrix should correspond to the left semi-infinte lead.

  H_LC  you should call it <seedname>_htLC.dat.
             This matrix should correspond to the Left Lead - Conductor
             coupling matrix.

  H_C    you should call it <seedname>_htC.dat.
             This is the matrix corresponding to the Conductor region or
             "central part" of your system (which probably contains the
             defect)

  H_CR you should call it <seedname>_htCR.dat.
             This matrix corresponds to the Conductor - Right Lead coupling
             matrix

  H_R   you should call it <seedname>_htR.dat.
            This corresponds to the Right Lead matrix.

You should look at the Wannier user guide to find the format of those files.
Those are basically Hamiltonian matrices expressed in the Wannier basis of
the corresponding piece of your system (Left Lead, Conductor, Right Lead).

Also you should know that the next release of the Wannier90 code should
have this 'lcr' type of calculations *completely automated* such that the
code will directly compute the Quantum Conductance automatically. So you
will not have to do anything, just like in the 'bulk' case!

Cheers,

Nicolas Poilvert


-- 
POILVERT Nicolas
PhD candidate,
Dpt of Materials Science and Engineering
Massachusetts Institute of Technology
77, massachusetts avenue
Cambridge, MA 02139
USA
work: (617) 452-4212
nicolas.poilvert at gmail.com
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