Specific Heats of Cu, GaAs, GaSb, InAs, and InSb from 1 to 30°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 ($\frac{c_{\mathrm{fc}}}{T}\sim 5$ μJ/${\mathrm{K}}^2$ g at.) to explain the low-temperature data. The inclusion of this term results in excellent agreement between calorimetric and elastic-constant values of ${\Theta }_0$. A reduced plot of $\frac{\Theta }{{\Theta }_0}$ versus $\frac{T}{{\Theta }_0}$ shows a minimum (0.7 at approximately $\frac{T}{{\Theta }_0}=0.05\mathrm{}$ which varies with average mass in both depth and location. The reduced $\frac{\Theta }{{\Theta }_0}$ 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 (${\Theta }_0=347\mathrm{}°$K, $\overline{M}=72.32\mathrm{}$) coincides with that of Si (${\Theta }_0=645\mathrm{}°$K, $M=28.086\mathrm{}$) instead of Ge (${\Theta }_0=374\mathrm{}°$K, $M=72.59\mathrm{}$), as might be expected. These heat-capacity data are used to recalculate temperature-dependent Grüneisen parameters from previous thermal-expansion data.