Conventions of the Hamiltonian

The code has 3 Hamiltonian implemented: A magnetic Hamiltonian based on an extended Heisenberg scheme, an phonon Hamiltonian and a tight binding Hamiltonian.

The magnetic Hamiltonian

The magnetic Hamiltonian can be written in the form H=c_J * \sum_(i,j) J_ij M_i M_j + ...

Units

The units are becoming a problem in Matjes. There is therefore a unit converter implemented in the code so that people can use whatever they want. The units of the code are

• eV for the energies
• atomic mass units for the masses
• fs for the time
• nm for the distances
• Tesla for the magnetic fields
• eV for the force constants
• Kelvin for the temperature
• V/nm for the electric field
• C.nm for the born effective charge
• the magnetization and the atomic displacements have no units

in the files constant.f90, all units are being converted. There is also a basic unit converter that is implemented but not linked in the code yet. I am looking for the best place to put it.