Lab 3 is due Friday, Mar 25th 11:59 pm

Computational Lab 3

Periodic Boundary Conditions-Local Optimization of Bulk Gold and Gold surfaces with DFT

Part 3: Creating a Slab

In this portion of the lab, you will tranform your bulk gold (infinite in 3 dimensions) into a slab (infinite in 2 dimensions).
In the third dimension, the resulting surface is exposed to vacuum.
In this portion of the lab you will consider the stability of different cuts of the bulk materials.

1. Copy the directory /home/fri/lab_files_2022/lab3/Slab to your ~/lab3 directory.
   
2. In this directory are two directories with larger bulk structures called fcc100bulk and fcc111bulk. Optimize the lattice constants of both of these structures with the ISIF=3 tag as you did in previous parts.
3. Next we will take these optimized bulk structures and convert them into slabs where one dimension is exposed to vacuum. The slab for the fcc (111) structure is already set up for you and is in the directory called Slab111. Optimize the slab and get its energy. No change id needed. Note that you are no longer optimizing the lattice constants. So you only need to optimize these structures until the last force is less than your convergence criteria.
4. The directory called Slab100 has all VASP starting files except for the POSCAR. You need to create the slab from your optimized bulk structure in fcc100bulk. First copy the CONTCAR file in fcc100bulk into the directory, Slab100.
5. Run the script cartesian.py to convert your CONTCAR file into a POSCAR file that is in cartesian coordinates and with the bottom two layers frozen.
6. Edit your new POSCAR file to have 10 Angstroms of vacuum in the z direction. You can simply make the third lattice vector 10 Å longer.
7. Relax the slab.