SUPERCELL

You can very easily go from a slab (look previous example) or a decimated interface to a repeated supercell calculation. In the above 8 atom slab example you make a supercell by just using in line 19 INTERFACE=F and changing line 13 to 0.0 0.0 4.0 . Then your system is periodically repeated. A different fast algorithm will be used to invert the Dyson in this case since the matrix is not a simple band diagonal matrix any more. Alternatively you could use option 'sparse'. The size of the principal layer is found in a similar way as demonstrated earlier in this manual. If you are not sure that the fast inversion algorithm will work in your case you can always use "full inv" to make Full inversion. Note here that the LATTICE=1 (line 9 on Fe bulk example) should also be changed to something like LATTICE=2 (or any other number) or else you would be using the 2D k-points in your 3D supercell calculation. Alternatively you can erase all k-points files in the mesh directory to be sure that correct k-points are created.