Relations between the zinc-blende and the NaCl structure type

Abstract

A new model for the transformation from the zinc-blende to the NaCl type is developed on the basis of the deformation of a 4-connected heterogeneous sphere packing in space group P3(2). The geometrical features of this transition are discussed by investigating the analogous deformations of a 4-connected homogeneous sphere packing in the supergroup P3(2)21 of P3(2). In this space group, the atomic arrangement corresponds to a diamond configuration. During the phase transition, it is deformed under preservation of all sphere contacts until a cubic primitive lattice is reached, the analogue of the NaCl arrangement formed by like atoms. The intermediate structure that occurs between the zinc-blende and the NaCl type is compared with the cinnabar type.

Bilayer sliding mechanism for the zinc-blende to rocksalt transition in SiC

“…In another study of the transition mechanism, using sphere packing methods and no energy considerations, Sowa also obtained the Imm2 subgroup mechanism 20 and more recently proposed an additional mechanism with P3 2 symmetry. 21 Catti 16 and Sowa 20,21 have noted that in the Imm2 and P 3 2 TPs no silicon-carbon bonds are broken. However, no further study is reported on the comparison of the two TPs.…”

Orientation relations between four phases of AgI

“…Limpijumnong, Lambrecht, 2001;Sowa, 2001Sowa, , 2005aShimojo et al, 2004) and between zincblende-and NaCl-type structures (e.g. Sowa, 2000bSowa, , 2003Shimojo et al, 2000;Catti, 2001;Hatch et al, 2005). Experimentally determined relations between the orientations of the structures before and after a phase transition may support or disprove possible transition models.…”

The cubic limiting complexes of lattice complexes with trigonal characteristic symmetry

“…The occurrence of sphere-packings with cubic inherent symmetry within trigonal lattice complexes (cf. Sowa, Koch and Fischer, 2003;Sowa andKoch, 2004, 2005) were used for checking the Table. Altogether, 10 invariant and 8 univariant cubic lattice complexes occur as limiting complexes within the trigonal crystal system. All lattice complexes of types (ii) and (iiia) (cf.…”

“…Consequently, a possible transition path may be described with the aid of a lattice complex having as well Fd 3 3m 8a (cubic diamond configurations, D) as Pm 3 3m 1a (cubic primitive lattices, P) as limiting complexes. Sowa (2003) showed that P3 2 21 6c is one of the lattice complexes with this property. As listed in Table 1, Pm 3 3m 1a occurs two times as limiting complex, namely at 1 = 3 1 = 3 1 = 4 and at 2 = 3 2 = 3 1 = 4 .…”

“…Fd 3 3m 8a can even be found four times, namely at 1 = 3 1 = 3 1 = 8 , 2 = 3 2 = 3 1 = 8 , 1 = 3 1 = 3 3 = 8 , and 2 = 3 2 = 3 3 = 8 , also with c/a ¼ ffiffi ffi 6 p . According to the transition path described by Sowa (2003), the atom at 1 = 3 1 = 3 1 = 8 moves to 0 1 = 3 1 = 12 , a position symmetrically equivalent to 2 = 3 2 = 3 1 = 4 . The axial ratio c/a, referred to P3 2 21, is the same before and after the phase transition.…”