Nanosurf Lab

The “tip_e_str.inp” file contains informations about the density of states of the tip. Than we need to run the FIREBALL code with the following settings of “fireball.in” file:

&OPTION part

‐ basisfile = <filename>
‐ lvsfile = <filename>
‐ kptpreference = <filename>
‐ nstepf = 1
- ifixcharge= 1

&OUTPUT part

- iwrtdos = 1

Last thing which we have to do is to write the “tip_g_str.inp” file. This file contains the geometrical structure of the tip. The xyz atom coordinates should be written there at the same order as we used for the “tip_e_str.inp” file, with the apex atom at first position. The file could looks like this:

1 5 ! natoms_tip_contributing, natoms_tip 0.000000 0.000000 0.400000 1 9 ! x, y, z, atomic type, # of orbitals 1.590800 1.590800 1.590800 1 9 ! x, y, z, atomic type, # of orbitals
1.590800 ‐1.59080 1.59080 1 9 ! x, y, z, atomic type, # of orbitals
‐1.590800 1.59080 1.59080 1 9 ! x, y, z, atomic type, # of orbitals
‐1.590800 ‐1.59080 1.59080 1 9 ! x, y, z, atomic type, # of orbitals
3 ! number of shells in each type of atom
0 1 2 ! l for each shell in atom type=1
‐2.0 4.0 81 ! energy initial, range and steps in dos file

But be carefull, the energy in the STM code is related to the Fermi level. When Fermi level is -2 eV from FIREBALL in the “tip_g_str.inp” in it's last line the first value has to be 0.0 (energy initial - Fermi level)