Hi,
I am trying to create a B2 NiTi (bcc lattice) with nickel atoms at corners and titanium at the center. I am using an EAM potential in setfl format. I have two inquiries.
(1) In the potential file, the third line has only the number 2 referring to the number of types of atoms but no listing of the element types following the number. I was not able to use pair_coeff command with the potential file like that. Is there any way to use pair_coeff commands that reads file ? However, I manually put Ni and Ti following 2, there’s no error regarding reading the potential file. I’m not sure if it’s okay to do so.
(2) After modifying the potential as above, I have another problem now. During relaxing the crystal (using minimize command), atoms are getting out of the box. Using ‘s’ (shrink-wrapped) boundary conditions I can get rid of lost atom issue but it’s giving unrealistic energy after relaxation. For example, if I displace a group of atoms (rigid shear of upper block on top of lower), minimization occurs within one timestep and total energy is even lower then initial crystal structure (which is weird). Please see below; any comments would be greatly appreciated. Thanks.
units metal
boundary p f p
atom_style atomic
region supercell block 0 9 -84.8528 84.8528 0 4.2426 units box
create_box 2 supercell
lattice custom 3.00 a1 1.0 0.0 0.0 a2 0.0 1.0 0.0 a3 0.0 0.0 1.0 &
basis 0.0 0.0 0.0 &
orient x 1 0 0 orient y 0 1 1 orient z 0 -1 1 origin 0.9 0.9 0.9
create_atoms 1 region supercell
lattice custom 3.00 a1 1.0 0.0 0.0 a2 0.0 1.0 0.0 a3 0.0 0.0 1.0 &
basis 0.5 0.5 0.5 &
orient x 1 0 0 orient y 0 1 1 orient z 0 -1 1 origin 0.9 0.9 0.9
create_atoms 2 region supercell