Ordering and correlation of cluster orientations in CaCd₆

Peter Brommer (1) , Franz Gähler (2) , Marek Mihalkovic (3)

1 Institut für Theoretische und Angewandte Physik
2 Institut für Theoretische und Angewandte Physik
3 Institute of Physics

In order to study the low temperature phase transition in CaCd₆, which is attributed to a reordering of the innermost tetrahedral cluster shells, accurate Embedded-Atom-Method potentials are developed for this system. With these potentials, the ideal cluster structure and the couplings between neighbouring clusters are determined. From these data, an effective hamiltonian for the cluster orientations is derived. The hamiltonian is used in Monte Carlo simulations, which exhibit a sharp peak in the specific heat at the expected transition temperature.

Mots clés: Physical Sciences

Peter Brommer, Franz Gähler, Marek Mihalkovic. Ordering and correlation of cluster orientations in CaCd₆. Philosophical Magazine, 2007, 87 (18-21), pp.2671-2677. ⟨10.1080/14786430701361370⟩. ⟨hal-00513835⟩