MgO VASP Tutorial edited by Lee,BooYoun, reference below.

 

This tutorial gives a brief introduction to VASP (Vienna Ab-initio Simulation Package).  The tutorial will describe the input and output files, teach you how to run a basic calculation, and teach you what is necessary to get an accurate calculation.

Prerequisites <Visualizer could be both VESTA or Xcyrsden, both are open source, wide spread.>

 

Introduction :                                                                                                  

VASP is a pre-packaged code that solves the Schrodinger Equation using appropriate approximations for the energy and forces.  DFT codes like VASP are a very powerful tool for scientific research.  However, you have to learn to frame your research questions around the outputs that a DFT code will give you.  This tutorial will focus on the VASP input and output files, however the same ideas can be applied to any DFT code although they will have different input/output.  As J. Hafner et al (MRS Bulletin, Vol 31, Sepember 2006) says:

 

The successful application of DFT to a materials problem involves three distinct steps: (1) translation of the engineering problem to a computable atomistic model, (2) computation of the required physicochemical properties, and (3) validation of the simulation results by confrontation with laboratory experiments.

 

The fundamental input parameters for VASP are:

• Atomic structure.  This can be …

  • any crystal structure (FCC, BCC, HCP, etc …) with your desired atoms.

  • a bulk or surface.

  • a structure including defects, interstitials, etc …

  • etc …

• Information about the electronic structure (see details in INCAR, POTCAR in this document)

• Convergence parameters (see details in INCAR, KPOINTS in this document)

 

For a given atomic structure, the fundamental outputs from VASP are:

• Energy & force

• Volume

• Magnetic Moment (if you are doing a spin-polarized calculation)

• DOS (Density of States)

 

There are other outputs, but the above 4 are the most fundamental and important.  Here are a few basic examples of what research questions these 4 outputs will give you:

• Stable structure

  • For an atom N (N=any atom in the periodic table), find the most stable crystal structure. For example: Set up Fe in FCC, BCC, and HCP crystal structure.  Compare the final energies for each structure to find the lowest energy crystal structure. 

  • Can also do as a function of pressure

• TMR (tunneling magnetoresistance) values (based on the s-DOS at the Fermi energy)

• Formation Energies

• Stable magnetic ordering