Abstract
We present phase diagram of materials (Silicon, Carbon, and Titanium disilicide TiSi2) obtained by the first principles and semi-empirical free-energy calculations. Phase boundary of the two solid phases of TiSi2 was found to sensitively depend on the pressure, which explains the suppressed phase transition in the thin films where the interfacial stress is large. The Clapeyron slope of the graphite-liquid phase boundary was found to rather suddenly decrease at about 1 GPa because of the change in the liquid structure. The structural change is continuous, but becomes first-order like only at lower temperature range where the liquid is metastable.
