Debye temperatures and cohesive properties

Abstract

Values of crystalline‐solid Debye temperatures depend both on the method and temperature of measurement. Simple relationships between Debye temperatures and such cohesive properties as compressibility and melting point were derived over 60 years ago by Madelung, by Einstein, and by Lindemann. Debye temperatures Θ_XR of a number of piezoelectric semiconductors with chalcopyrite structure have been determined at room temperature by x‐ray diffraction. A new series of heat capacity measurements over the temperature range 1.2–40 °K, for four chalcopyrites, give Θ_D values at 0 °K. A common proportionality is found between each of these Θ_XR and Θ_D values and microhardness, and also melting point: Acceptable reproducibility is given for the A^IB^IIIC^VI₂ chalcopyrites and, separately, the A^IIB^IVC^V₂ compounds. Values of Θ are predicted for 15 additional chalcopyrites. Excellent proportionality between Θ_elastic and compressibility is found for the europium chalcogenides, based on the data of Shapira and Reed.