Molar heat capacities of cdte, hgte and cdte-hgte alloys in the solid state

Abstract

Using a differential scanning calorimeter, the molar heat capacities of the two components HgTe and CdTe and of ten solid alloys of the CdTeHgTe system were measured at constant pressure between 300 K and 523 K. Irregular variations of the C p = φ( T) curves of CdTeHgTe alloys suggest the existence of a solid state miscibility gap in this system. The limit of the (solid ↔ solid (1) + solid (2)) miscibility gap and coordinates of the critical temperature ( χ CdTe ≠ 0.55, T = 455 K) are proposed. From C P data obtained in a single-phase solid region, the excess molar heat capacities ( ΔC P = C p(exp)− C p(calc)) at 500 K were deduced: the maximum negative excess C P is located at χ CdTe = 0.5.