Ok, i used material studio for starch and other complex materials and large chains. But the method will be generally the same for all materials.
Here are the steps (more or less) that i followed :
- Creat the chain (or the material in yout case GeTe) via MS.
- Apply energy and geometry minimization.
- Creat an amorphous cell (using the amorphous cell builder in material studio) where you can choose the density etc ..; you can start with a value close to experimental data but in either cases the system afterwars should approach to this value.
-Run MD simulations
You should make sure that you use the same forcefield along all of the steps above.