
This example shows how to use pw.x and pwcond.x to compute the complex band 
structure (CBS) and transmittace within DFT+U for an Au monatomic chain with 
a CO impurity. The Hubbard potential is included in the coefficients of the 
non-local part of the pseudopotential (PP), as described in:
http://www.sissa.it/cm/thesis/2010/SclauzeroG_PhDthesis.pdf

The plain LDA result is compared with the LDA+U result (using U=3 eV), 
therefore the following calculations are performed first without, and 
then with the Hubbard U potential.


1.) Visualization of the CBS:

 a) A pw.x calculation provides the self-consistent potential for a perfect 
    Au monatomic chain (1 atom per cell).

 b) A pwcond.x calculation gives for every energy in the chosen range the CBS
    of the Au chain. Notice how the 5d-states of Au are pushed away from the 
    Fermi energy by the Hubbard U potential.


2.) Calculation of the transmittance through the chain with the impurity:

 a) Two pw.x calculations provide the self-consistent potentials for a perfect
    Au chain (used as left and right lead) and for a Au chain (6 atoms long) 
    with a CO molecule adsorbed atop the central Au atom (scattering region).

 b) A pwcond.x calculation gives the transmittance through the Au chain with 
    the adsorbed impurity for selected energies around the Fermi level.


You can plot the results with Gnuplot using the automatically generated script.


N.B.: 1. In order to make the tests faster, these calculations are not fully 
         converged with respect to k points, cut-off and size of the cell.
      2. The PP must contain the AE wavefunctions for the valence orbitals
         that are included in the Hubbard term (e.g. using lsave_wfc=.true.
         when generating the PP through ld1.x).
