THE ANTIFERROELECTRIC PHASE TRANSITION IN THE CH3NH3PbCl3 STUDIED BY MEANS OF PSEUDO-SPIN MODELS

A. Maalej1*, F. Karray2, A. Kallel2, Y. Abid1

1 L.P.M.C. Faculté des Sciences, département de physique, B. P. 802, 3018 Sfax, Tunisie

2 L.G.D. Faculté des Sciences, département de physique, B. P. 802, 3018 Sfax, Tunisie

* Corresponding author. E-mail : Adel.Maalej@fss.rnu.tn

Received : 30 April 2002; revised version accepted : 12 August 2002

Abstract

The crystal of CH3NH3PbCl3 (MAPbCl3) exhibits two order disorder phase transitions. A previous structural study shows two phase transitions according to the phase sequence:

Phase I (Pmm ) Phase II ( P4/mmm ) Phase III ( P2221 ).

Three pseudo-spin models are used to describe the mechanism of the phase transitions and predict the antiferroelectric phase ( phase III ). Pseudo-spin coordinates associated to the orientational disorder of the methylammonium ( MA ) groups, acting as order- parameters ( O.P.’S ) are considered.

Keywords : CH3NH3PbCl3 (MAPbCl3); Order disorder phase transitions; Pseudo-spin coordinates; Antiferroelectric phase.

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