Characteristic non-Debye heat capacity formula applied to GaN and ZnO

Abstract

Characteristic non-Debye behaviors of heat capacity data, Cp(T), which are mainly manifested in the form of non-monotonic dependences (maxima) of the respective Cp(T)/T3 curves in the cryogenic region, are described by means of an unprecedented interpolation formula. Least mean square fittings of duly comprehensive Cp(T) data sets available for GaN and ZnO show excellent agreement, from the liquid-helium-hydrogen region up to high temperatures. We show that, in contrast to misleading suggestions made in some recent thermo-physical papers, Debye’s heat capacity formula used under the presumption of a fixed Debye temperature is clearly incapable of providing reasonable numerical simulations of measured Cp(T) dependences.