Krypton on graphite: Microstructure at zero temperature

We have calculated the energy associated with different possible configurations of a krypton monolayer on graphite using a microscopic model for the Kr-Kr and Kr-graphite interactions. In the latter case, there is considerable uncertainty with regard to the choice of potential, and calculations have been carried out for a range of parameters. For a potential which is weakly modulated parallel to the graphite plane (such as the one suggested by Steele) the lowest energy per atom is found to be a hexagonal nonregistered configuration. If the modulation is increased by a factor of 2, the (√3×√3) registered configuration becomes the lowest-energy configuration and there will also then be a regime in which hexagonal and striped phases differ in energy by less than 1 K. For the range of potentials of interest, the domain walls are found to be broad and in agreement with predictions from continuum theory.