Comparison of different empirical potentials for energy calculation of grain boundaries in silicon at OK

We compare several empirical potentials commonly used in coincidence grain boundary studies. Such potentials are unable to describe all deformations with accuracy. In some cases, the uncertainties are larger than the energy difference between two structures of the same coincidence orientation and these potentials cannot describe them. We have also performed calculations with a more recent potential which takes a four body interaction into account. This potential describes all deformations with accuracy and shows that good results cannot be obtained with usual potentials.