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The tight-binding parameters were fit to first-principles Linearized Augmented Plane Wave (LAPW) results over the following ranges:
| Structure | Minimum Lattice Constant (Bohr) | Maximum Lattice Constant (Bohr) |
| fcc (A1) | 7.10 | 8.10 |
| bcc (A2) | 5.80 | 6.30 |
| simple cubic (Ah) | 5.00 | 5.50 |
| diamond (A4) | 11.55 | 11.80 |
| hcp (A3) (a) | 5.12 | 5.30 |
| hcp (A3) (c) | 8.36 | 8.65 |
| Reference | Phys. Rev. B 57, R2013-6 (1998) | |
Use of the parameters outside of these ranges may result in unphysical behavior.
The previous parameters were chosen to optimize cubic structures, and we allowed the t2g and eg onsite parameters to be different. [For a detailed discussion of this see the discussion of Vanadium at the bottom of page 4521 in Phys. Rev. B 54, 4519 (1996).]
Other calculations, such as stacking faults, dislocations, hexagonal systems, anything which requires rotations about an axis, etc., require that the t2g and eg onsite parameters be equal. We have developed an Aluminum parameter set with these properties. Otherwise it was fit to the same database as the above parameters, and has similar physical behavior.
This parameter set was using to calculate stacking fault energies in Aluminum [ Phys. Rev. B 61, 4894 (2000).]
Get the parameters (al_par_t2g_eq_eg).