Abstract:
The e ciency of combining the concept of superspatial symmetry and the
ideas of the lattice model for the calculation of the model phonon spectra
of complex crystalline formations is shown. 3 + 3- dimensional bases, sets
of modulation vectors and (4 × 4a × 4a) lattice model for the description
of crystal structure are presented and calculations of model phonon spectra
and state densities of Nb3Sn and Nb3Ge structures at di erent combinations
of force constants are given. As a result of the analysis it is shown that at
the choice of certain combinations of power constants, mainly α4, α5 and
α6, it is possible to obtain phonon spectra with optical frequencies in 150- 240 cm−1 range, which correlates with the experimental data. However,
the distribution of densities in the spectra of phonon states is signi cantly
di erent, which may re ect the signi cant lability of the chemical bond in
these compounds, despite the binary nature of their composition.
Description:
I.I. Nebola, A.F. Katanytsia, I.M. Shkyrta, D.I. Kaynts,Yu.O. Pal, I.I. Ochkay. Model phonon spectra and densities of states of Nb3Sn and Nb3Ge structures. Small Triangle Meeting Medzilaborce, October 2528, 2022. Р. 1-7.
