I want to construct a position files containing some layers of Pt 111 and Pt 100 surafces using some realistic parameters . any kind of lattice is fine. Relevent documention or position file or the code is welcome.
You can construct such systems in LAMMPS using a combination of the region, lattice, and create_atoms commands. But there are also more capable and flexible tools around. A few are listed here: https://lammps.org/prepost.html others are discussed in other categories of the discourse forum or you have to look around. A few properly designed searches on the web should give you lots of suggestions.