Isostructural solid - solid transitions in systems with a repulsive `shoulder' potential

Using Monte Carlo simulations, we study the phase behaviour of systems with a short-ranged repulsive `shoulder' potential. In analogy to systems with a short-ranged attractive interaction, the shoulder potential leads to an isostructural solid - solid phase transition. We show that the range of interactions for which a solid - solid transition is possible is much wider for repulsive than for attractive interactions.