Title: STRUCTURE SIMILARITY AND LATTICE DYNAMICS OF InSe AND In_4Se_3 CRYSTALS
Author(s): D.M.Bercha (Uzhgorod State University, 54 Voloshin Str., UA-294000 Uzhgorod, Ukraine; Institute of Physics, Pedagogical University of Rzeszow, Rejtana 16a, PL-35-310 Rzeszow, Poland), K.Z.Rushchanskii, L.Yu.Kharkhalis (Uzhgorod State University, 54 Voloshin Str., UA-294000 Uzhgorod, Ukraine), M.Sznajder (Institute of Physics, Pedagogical University of Rzeszow, Rejtana 16a, PL-35-310 Rzeszow, Poland)

In the work it was shown that the In$_4$Se$_3$ crystal is similar by its dynamical properties to the InSe modulated crystal. The transformation of the $D_{6h}^4$ symmetry group of $\beta$-InSe crystal to $D_{2h}^9$ group of the In$_4$Se$_4$ structure and the $D_{2h}^{12}$ group of In$_4$Se$_3$ structure has been investigated. In spite of structure corrugation of In$_4$Se$_3$ layer, it is shown that the region of the weak bond in this crystal by the dynamical characteristics is similar to the weak bond region in InSe crystal.

Comments: Figs. 5, Refs. 9, Tabs. 0.