Once we have the “CHARGES” we can produce the “Atomo_i” files by the FIREBALL. “CHARGES” file has to be at the same directory when you are running the FIREBALL. To the “fireball.in” we will write:
‐ nstepf = 1
‐ ifixcharge = 1
‐ iwrtatom = 1
Than you obtained “Atomo_i” files and the “struc.inp” file, which should be modified to work properly when you run the STM simulation. How to do that: The “struc.inp” file contains some information about the sample:
50 ! number. of atoms in unit cell 1 45 ! initial and final atom which is contributing to the tunneling current 12 ! number maximum of neighbours 0.000000 0.000000 0.000000 1 ! coordinates and type of each atom . . . 4 ! number of orbitals in each type of atom (in a row) 2 ! number of shells of each atom type (in a row) 0 1 ! l of each shell type atom=1 (each atom type in a row) 16 ! nkprl: no. of k's in one row (nk=nkprl2), =0 read a samplek.kpts file 1 1 ! index_cell1, index_cell2 (ncell = (2*index_cell1+1)*(2*index_cell1+1)) 0.866025 , 0.5 , 0. ! Horizontal lattice vector (x‐axis) 0.866025 , ‐0.5 , 0. ! Horizontal lattice vector (y‐axis)
!! We have to delete the last row of Lattice vector (the third one)
The fixing the “nkprl” value to 0 and using the fireball k-points (with the opposite to complete the Brouilloin) is strongly reccomended. The “index_cell1” and “index_cell2” are relative to the number of cells we need in each direction x and y to avoid the border problems. The product of them gives us number of repetition unit which influence is involved to the computation.