Electron-Phonon Interaction as a Mechanism of Phase Transition in the CuInP₂S₆Crystal

Abstract

Studies on the phases of CuInP2S6 crystal exhibiting phase transitions of the order-disorder type are performed.A possibility for the cooperative JahnTeller eect to occur in this crystal is analyzed. For this purpose, the procedure of constructing the potential energy matrix is generalized for the case of crystal and it is illustrated by the construction of the adiabatic potentials for Γ5−Γ5 vibronic coupling for the proto-and paraelectric phases of CuInP2S6. The structure of the obtained potentials is analyzed together with the discussion on the appearance of spontaneous polarization in this crystal.

Van der Waals layered ferroelectric CuInP2S6: Physical properties and device applications

“…It comes more like a posteriori based on other related systems from the stereochemical viewpoint [45]. Bercha and coworkers conducted the first detailed discussion on the origin of the spontaneous polarization and phase transition by combining group theory analysis and DFT-based ab initio calculations [91,92]. Starting from a high-symmetry trigonal proto structure, they correlated the elementary energy band splitting with the symmetry lowing of the lattice towards the paraelectric phase.…”

Metal Thio‐ and Selenophosphates as Multifunctional van der Waals Layered Materials

“…More recently, Bercha et al calculated the band diagram for CuInP 2 S 6 using DFT‐based ab initio theory to model the Jahn–Teller effect and its contribution to ferrielectric ordering in this compound.…”

van der Waals forces control ferroelectric–antiferroelectric ordering in CuInP2S6 and CuBiP2Se6 laminar materials

“…Bulk materials of the form ABP 2 X 6 often take on a laminar shape and are of considerable current interest as possible ultrathin materials for use as ferroelectrics in memory storage and other devices. Bulk systems investigated in this context include: CuInP 2 S 6 , [11][12][13][14][15][16][17] CuBiP 2 Se 6 , 18 AgBiP 2 Se 6 , 18 AgBiP 2 S 6 ,…”