Dhe. Gross et al., MICROCANONICAL THERMODYNAMICS OF FIRST-ORDER PHASE-TRANSITIONS STUDIED IN THE POTTS-MODEL, Annalen der Physik, 5(5), 1996, pp. 446-452
Phase transitions of first and second order can easily be distinguishe
d in small systems in the microcanonical ensemble. Configurations of p
hase coexistence, which are suppressed in the conventional canonical f
ormulation, carry important information about the main characteristics
of first order phase transitions like the transition temperature, the
latent heat, and the interphase surface tension. The characteristic b
ackbending of the microcanonical caloric equation of state T(E) (not t
o be confused with the well known Van der Waals loops in ordinary ther
modynamics or mean field approximations) leading to a negative specifi
c heat is intimately linked to the interphase surface entropy.