Elucidation of simple pathways for reconstructive phase transitions using periodic equi- surfaces (PES) descriptors

摘要

A short topological pathway relating two fundamental three-dimensional, three-connected networks as they are found in alpha-ThSi_2 and SrSi_2 is proposed. The approach exploits a Fourier function approach based on periodic nodal (PNS) and periodic cqui-surface (PES) descriptors. Continuous functions are chosen to represent the networks in question and a linear transition approach provides a transition model. On this basis, each network is fragmented into a collection of dumb-hells, and the transition is described in terms of a concerted reorientation of the latter. The centers of mass of the dumb-bells are shown to conserve the diamond topology at each stage of the transition, as an underlying motif of the whole process.