SPECIFIC HEATS OF CU GAAS GASB INAS AND INSB FROM 1 TO 30 DEGREES K

The specific heats of Cu, GaAs, GaSb, InAs, and InSb have been measured over the temperature range from 1 to 30°K with an accuracy of 0.5%. A comparison of the copper data with other published data verifies this estimate of the accuracy. The analysis of all four III-V compounds requires the inclusion of a free-carrier term linear in the temperature (cfcT∼5 μJ/K2 g at.) to explain the low-temperature data. The inclusion of this term results in excellent agreement between calorimetric and elastic-constant values of Θ0. A reduced plot of ΘΘ0 versus TΘ0 shows a minimum (0.7 at approximately TΘ0=0.05 which varies with average mass in both depth and location. The reduced ΘΘ0 curves for Ge and Si show qualitatively the same relative mass dependence but do not fall quantitatively into the pattern established by the compounds. The curve for GaAs (Θ0=347°K, M̄=72.32) coincides with that of Si (Θ0=645°K, M=28.086) instead of Ge (Θ0=374°K, M=72.59), as might be expected. These heat-capacity data are used to recalculate temperature-dependent Grüneisen parameters from previous thermal-expansion data. © 1968 The American Physical Society.