Quasicrystals in a monodisperse system

We investigate the formation of a two-dimensional quasicrystal in a monodis perse system, using molecular dynamics simulations of hard-sphere particles interacting via a two-dimensional square-well potential. We find that more than one stable crystalline phase can form for certain values of the squar e-well parameters. Quenching the liquid phase at a very low temperature, we obtain an amorphous phase. By heating this amorphous phase, we obtain a qu asicrystalline structure with fivefold symmetry. From estimations of the He lmholtz potentials of the stable crystalline phases and of the quasicrystal , we conclude that the observed quasicrystal phase can be the stable phase in a specific range of temperatures. [S1063-651X(99)07909-X].