Anisotropy of dynamic parameters of the In4Se3 lattice

Thermal coefficients of αsub(i) expansion, X-ray characteristics of the temperature THETAsub(psub(i)) and mean-square atomic displacement (usub(i)sup(2)) of In4Se3 lattice within the temperature range of (90-300) K are determined on the basis of temperature dependences of lattice periods and relative integral intensities of diffraction maxima (400), (0160), (0016). Magnitudes of the measured physical values are different along main crystallographyc directions, which reflects anisotropic character of bonding forces of laminated compound. Quasi-two-dimensional pattern of phonon spectra of In4Se3 lattice leads to great changes in such dynamic parameters as αsub(b), THETAsub(psub(b)), THETAsub(psub(b)), THETAsub(psub(c)) versus the temperature and to large anisotropy of mean-square shifts (usub(z)sup(2))/(usub(i)sup(2)) approximately 3