Effective Medium Theory (EMT)
The EMT potential is the main Calculator in Asap, and the raison d'être of Asap. It is a many-body potential, giving a good description of the late transition metals crystalling in the FCC crystal structure. The elements described by the main set of EMT parameters are Al, Ni, Cu, Pd, Ag, Pt, and Au, the Al potential is however not suitable for materials science application, as the stacking fault energy is wrong.
In addition to the default EMT parameters, it is possible to use a ParameterProvider to provide an alternative set of EMT parameters. In this way, it is possible to use EMT potentials for Ru as well as for Mg-Cu and Cu-Zr metallic glasses.
The following parameter providers are available.
- The default EMT parameters, as published in [XX].
- An alternative set of parameters for Cu and Ag, reoptimized to experimental data including the stacking fault energies by Torben Rasmussen.
- The default EMT parameters for simulations where distances are interpreted as in bohr instead of Å, and time units are changed similarly. Do not use unless you know what you are doing. In fact, using this is probably a sign of not knowing what you are doing. It will soon be removed.
- Allows the parameters to be set individually from Python. This provider is used for optimization, but is also used for the metallic glass EMT parameters together with the GetPotential function.
- Similar to EMTVariableParameterProvider but for HCP metals. Can currently be used for Ruthenium.