 --- GUIDE OF EXAMPLES ---

 This folder contains a number of example systems to test the unfolding tool.
 Run SIESTA to generate the .EIG, .HSX and .ion files, then run unfold to obtain
 the fully unfolded or refolded bands.
 
 Some Matlab routines are available in Src/ to plot the outputs (notice that examples
 of graphene generate a collection of files to be plotted with 'plotmesh.m').

 A brief description of the examples can be found below. For further details 
 see: https://arxiv.org/abs/1812.03925

 * Si:
 
  FCC bulk:  cubic supercell with 8 atoms. The example is trivial, refolding recovers
             the FCC bands. As the result is a density of states, band degeneracies are
             reflected in the plot.

  vacancy:   one atom is removed from the trivial supercell. A comparison with the 
             bulk bands reveals changes in the states.

  amorphous: extreme case of disorder. Full unfolding yields the effect of atomic 
             potential in the free e- dispersion relation. Refolding into the FCC
             vectors, a resemblance in the degeneracy distribution appears.
             ( a-Si coordinates ref: 
                      Igram et at., J. Non-Cryst. Solids 2018, 492, 27-32 )

  * C:
  
  diamond:  analogous to Si FCC bulk.

  graphene(**):

    585 divacancy: different supercell sizes yield very different conventional bands, 
                   whereas refolding into graphene lattice vectors reveals qualitatively
                   equivalent band behaviour. 
   
    rotated graphene bilayer: the fully unfolded bands show the interaction between
                   the states of both sublattices, their positions being rotated one 
                   with respect to the other. In particular, a saddle point emerges
                   from the interaction between the Dirac cones.
                   Refolding is meaningless, as there are two periodicities in the 
                   system and neither is prevalent over the other. However, the
                   RefoldingLatticeVector is present in the .fdf file as:
                      A1*1e-5
                      A2*1e-5
                      A3
                   then A1, A2 <<  => B1, B2 >>, so, in practice, the refolding vectors
                   in the x and y directions will be excluded by the RefoldingGcutoff.
                   Vector A3 is unaltered, which means that we refold over the periodic
                   images of the bilayer that were artificially introduced to perform
                   the DFT calculation. The actual fully unfolded bands will be those
                   stored in the .RefoldedBands files.



  (**) To test these examples, compile and run 'meshgen.c' before running unfold.

