  We report the first observation of temperature-controlled reentrant
transition in simulations of mixtures of small and big particles interacting
via soft repulsive potential in 2D. As temperature increases, the system passes
from a fluid mixture, to a crystal of big particles in a fluid of small
particles and back to a fluid mixture. Solidification is driven by entropy gain
of small particles which overcomes the free energy cost of confining big ones.
Melting results from enhanced interpenetration of particles at high temperature
which reduces the entropic forces that stabilize the crystal.
