  We investigate the formation of a two-dimensional quasicrystal in a
monodisperse 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
square-well parameters. Quenching the liquid phase at a very low temperature,
we obtain an amorphous phase. By heating this amorphous phase, we obtain a
quasicrystalline structure with five-fold symmetry. From estimations of the
Helmholtz 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.
