how_to_prepare_the_new_tip_and_sample_for_stm_simulations
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how_to_prepare_the_new_tip_and_sample_for_stm_simulations [2009/11/25 15:23] vroz |
how_to_prepare_the_new_tip_and_sample_for_stm_simulations [2011/02/18 13:13] (current) |
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| - | ==== I. The geometry ==== | + | ==== The geometry ==== |
| First of all we need the “*.bas” file of the tip and sample geometry | First of all we need the “*.bas” file of the tip and sample geometry | ||
| Line 23: | Line 23: | ||
| - | ==== II. The files we need ==== | + | ==== The files we need ==== |
| Line 108: | Line 108: | ||
| this script). | this script). | ||
| - | == I.II.I. The “run_hops.com” script: == | + | == II.II.I. The “run_hops.com” script: == |
| #!/bin/bash \\ | #!/bin/bash \\ | ||
| Line 136: | Line 136: | ||
| rm -f tip_sample_aux | rm -f tip_sample_aux | ||
| - | == I.II.II. The “README” file: == | + | == II.II.II. The “README” file: == |
| a short description how to generate hopping data \\ | a short description how to generate hopping data \\ | ||
| Line 165: | Line 165: | ||
| =======D. modify header of interacti_X_Y.dat file \\ | =======D. modify header of interacti_X_Y.dat file \\ | ||
| - | == Interactions for W(spd)-C(sp) using FIREBALL program == \\ | + | !*Interactions for W(spd)-C(sp) using FIREBALL program*! \\ |
| 57 !number of distances \\ | 57 !number of distances \\ | ||
| 2.00000 30.00000 !dist_min, dist_max \\ | 2.00000 30.00000 !dist_min, dist_max \\ | ||
| Line 177: | Line 177: | ||
| sample respectively.// | sample respectively.// | ||
| - | == Interactions for W(spd)-C(sp) using FIREBALL program == \\ | + | !*Interactions for W(spd)-C(sp) using FIREBALL program*! \\ |
| 57 !number of distances \\ | 57 !number of distances \\ | ||
| 2.00000 30.00000 !dist_min, dist_max \\ | 2.00000 30.00000 !dist_min, dist_max \\ | ||
| Line 189: | Line 189: | ||
| Look at the header: | Look at the header: | ||
| - | == Interactions for W‐Tid using FIREBALL program == \\ | + | !*Interactions for W‐Tid using FIREBALL program*! \\ |
| 57 \\ | 57 \\ | ||
| 2.000000 30.00000 \\ | 2.000000 30.00000 \\ | ||
| Line 205: | Line 205: | ||
| and d 2, the interaction pi will be 1 and delta 2. \\ | and d 2, the interaction pi will be 1 and delta 2. \\ | ||
| For long distances, we do the parallel planes approximation using | For long distances, we do the parallel planes approximation using | ||
| - | the expression: A.e The A (4th value in the row) is the independent value we | + | the expression: \\ |
| - | have to find. α (5th value) depends on the orbitals you have in the hoppings, the | + | |
| + | A.e<sup>-W.r</sup> | ||
| + | |||
| + | The "A" (4th value in the row) is the independent value we | ||
| + | have to find. "α" (5th value) depends on the orbitals you have in the hoppings, the | ||
| expression used is: α=l1+l2+1, but sometimes it could be changed depending on | expression used is: α=l1+l2+1, but sometimes it could be changed depending on | ||
| - | the fix conditions. Finally, the W (6th) is related with the work function of the | + | the fix conditions. The "W" (6th) is related with the work function of the |
| - | materials in the hopping: where ω’s are the work function for | + | materials in the hopping: |
| - | each kind of atom. There is no function as BEGIN or CREATE to calculate these | + | |
| - | long‐distance parameters, but there is a tool in the XEO program made by Daniel | + | W = ((ω<sub>T</sub> + ω<sub>S</sub>) / 2)<sup>1/2</sup> |
| - | Gonzalez. Here you have to change by hand the values of A till you “see” (with the | + | |
| + | where ω’s are the work function for | ||
| + | each kind of atom. There is no function as **BEGIN** or **CREATE** to calculate these | ||
| + | long‐distance parameters, but there is a tool in the **XEO** program made by Daniel | ||
| + | Gonzalez. Here you have to change by hand the values of "A" till you “see” (with the | ||
| eyes) a coincidence in the value and the derivative. Finally, let’s mention that the | eyes) a coincidence in the value and the derivative. Finally, let’s mention that the | ||
| 7th and 8th values in the row are related with the simple basis or double basis | 7th and 8th values in the row are related with the simple basis or double basis | ||
| case. When you have a double basis you need an extra parameter to differentiate | case. When you have a double basis you need an extra parameter to differentiate | ||
| - | from the simple basis orbital. The last value is the cut‐off radius. | + | from the simple basis orbital. \\ |
| + | The last value is the cut‐off radius. | ||
| - | \\ | + | Here you can download : \\ |
| + | ========================. \\ | ||
| + | ="run_hops.com" script \\ | ||
| + | ="README" file \\ | ||
| + | ========================. | ||
| - | ==== II.III. tip_g_str.inp ==== | + | \\ |
| + | |||
| + | === II.III. tip_g_str.inp === | ||
| Last thing which we have to do is to write the “tip_g_str.inp” file. This file | 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 | 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 | 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: | + | 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 5 ! natoms_tip_contributing, natoms_tip \\ |
| - | 1.590800 1.590800 1.590800 1 9 ! x, y, z, atomic type, # of orbitals | + | 0.000000 0.000000 0.400000 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 1.590800 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 | + | ‐1.590800 1.59080 1.59080 1 9 ! x, y, z, atomic type, # of orbitals \\ |
| - | 3 ! number of shells in each type of atom | + | ‐1.590800 ‐1.59080 1.59080 1 9 ! x, y, z, atomic type, # of orbitals \\ |
| - | 0 1 2 ! l for each shell in atom type=1 | + | 3 ! number of shells in each type of atom \\ |
| - | ‐2.0 4.0 81 ! energy initial, range and steps in dos file | + | 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)// | ||
how_to_prepare_the_new_tip_and_sample_for_stm_simulations.1259159000.txt.gz · Last modified: 2011/02/18 13:14 (external edit)
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