The Atomic Heat of Germanium below 4°K

The atomic heat of germanium below 4^∘{}K has been measured with pure polycrystalline and single crystal ingots, indium and antimony doped single crystal ingots, and pure crushed material. The lattice contribution is in all cases proportional to T³ and corresponds to a Debye temperature of (362±{}6)^∘{}K, which agrees with the value calculated from elastic constants. From the degree to which this cubic term represents the total measured atomic heat, the estimated upper limit for the ratio of the effective carrier mass to that of free electrons is found to be in the neighborhood of unity.