generation_of_tip_e_str.inp_files_for_stm_simulation
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generation_of_tip_e_str.inp_files_for_stm_simulation [2010/09/02 11:27] cegonzal |
generation_of_tip_e_str.inp_files_for_stm_simulation [2011/02/18 13:13] |
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| - | This page describes how to generate, using Fireball, the tip_e_str.inp with the retarded and advanced green functions and the density of states (DOS) for the STM program . | ||
| - | First, we need to obtain SCF-solution for particular geometry. Once we have it, we need to switch on these options: | ||
| - | ifixcharge = 1 | ||
| - | iwrtdos = 1 | ||
| - | |||
| - | Simulation parameters are defined in two additional files: | ||
| - | |||
| - | ---- | ||
| - | |||
| - | ''dos.optional'' | ||
| - | This file defines basic parameters of the DOS calculation. | ||
| - | |||
| - | 1.00000 ! ratio of lattice (for fractional coordinates, if xyz are in Angstroms maintain 1.000) | ||
| - | 1 5 ! natom_beg,natom_end (initial and final atom for the DOS calculation) | ||
| - | 401 ! number of energies (number of energies in the DOS calcuation) | ||
| - | -12.0 0.05 ! first energy (initial absolute energy (fireball's value is the Fermi Level) and energy step | ||
| - | 1 ! 1/0 yes/no write the tip_e_str.inp file for the DOS | ||
| - | -4.01 4.01 ! minimun and maximum energy limit for writing the green function in the tip_e_str.inp file | ||
| - | 0.05 ! imaginary part for the green function in the DOS calculation | ||
| - | |||
| - | ---- | ||
| - | |||
| - | One comment related with the minimum and maximum energy limits. Normally, we are interested in the range 2eV bellow and above the Fermi Level, but calculating a bigger range of DOS. These parameters give us the opportunity to do both things together: dos calculation and tip_e_str.inp fie generation. As an example we can consider a system with a FL=-2.0 eV and we want to generate the file from -2+FL to FL+2 doing the calculation of the complete DOS from -10 to +10 with an energy step of 0.05. The corresponding file is showed above. (Take a look to the minimum and maximum vales a little bit larger to avoid numerical bad effects). | ||
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generation_of_tip_e_str.inp_files_for_stm_simulation.txt ยท Last modified: 2011/02/18 13:13 (external edit)
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