# Bulk systems

A bulk system is a model for the part of matter which is not influenced by its surface. In this tutorial, let us focus on modelling crystals that have a small unit cell with periodic boundary conditions. You can learn how to perform density-functional-theory calculations and structure optimization in VASP.

## Further resources

For lectures, check here:

- Introduction to ab-initio simulation in VASP by Martijn Marsman
- Electronic Convergence by Martijn Marsman