Basic moments of phonon density of states spectra and characteristic phonon temperatures of group IV, III-V, and II-VI materials

摘要

We have redigitized a large variety of phonon density of states (PDOS) spectra, that have been published by diferent researchers for group IV (diamond, 3C-SiC, Si, and Ge), III-V (BN, BP, BAs, BSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, and InSb), and II-VI materials (ZnO, ZnS, ZnSe, ZnTe, CdS, and CdTe), including calculations of their moments, , of orders n(velence)-1, 1, 2, and 4. Notwithstanding the obvious differences in concrete shapes of spectra presented for one and the same material by different authors, the respective magnitudes of estimated moments have been found in most cases to be nearly the same (to within uncertainties of some few percent). For most materials under study, the average phonon temperatures of the lower and upper sections of PDOS spectra, (THETA)_(L) and (THETA)_(U), are found to be by factors of order 0.6 lower or 1.4 higher, respectively, than the average phonon temperature, (THETA)_(P), of the total PDOS spectra. The estimated high-temperature limits of Debye temperatures, (THETA)_(D)(infinity), are found to be significantly higher (by factors of order 1.4) than (THETA)_(P), implying an order-of-magnitude equality, (THETA)_(D)(infinity) approx= (THETA)_(U) (within differences not exceeding an order of +-10percent, for all materials under study). The phonon temperatures, (THETA)_(g), that are effective in controlling the observable temperature dependences of fundamental energy gaps, E_(g)(T), are found to be usually of the same order as the respective average phonon temperatures, (THETA)_(g) approx= (THETA)_(P). The existing differences between these two qualitatively different types of characteristic phonon temperatures are seen to be limited, for diamond, 3C-SiC, Si, Ge, AlN, GaN, GaP, GaAs, GaSb, InP, InSb, ZnS, ZnSe, ZnTe, and CdTe, to an order of +-12percent. We design an exemplary way for precalculating harmonic parts of isochoric heat capacities on the basis of the estimated quadruplets of PDOS spectra moments. This novel calculation scheme is exemplified for silicon and germanium.