Low temperature specific heat of GaP, InP, GaAs and InAs compounds

Low temperature specific heats of the GaP, InP, GaAs and InAs compounds were measured over the temperature range 4.5 to 298.15 K using an adiabatic calorimeter. The Debye temperatures were derived from the obtained specific heat data. The curves of Debye temperature as a function of temperature for the GaP, InP, GaAs and InAs compounds exhibit a minimum in the temperature range of 15-30 K and a maximum at somewhat higher temparatures (approximately 130∼180 K). The standard entropies of the GaP, InP, GaAs and InAs compounds determined from the specific heat data were 50.5, 62.1, 64.1 and 75.5 J/(mol·K), respectively. A relation was found between the standard entropy and the cohesive energy. The standard entropies of the III-V compounds decreased linearly with increasing cohesive energy per bond.