Highlights on the reversible nonpolar-to-polar P 3121- P 31 phase transition at low temperature in NaLa(SO4)2·H2O: mechanism and piezoelectric properties

H Azeroual; J-L Bantignies; D Maurin; D Granier; J Haines; O Cambon; P Hermet

doi:10.1039/d3cp00587a

Highlights on the reversible nonpolar-to-polar P 3₁21- P 3₁ phase transition at low temperature in NaLa(SO₄)₂·H₂O: mechanism and piezoelectric properties

Phys Chem Chem Phys. 2023 Mar 15;25(11):8168-8179. doi: 10.1039/d3cp00587a.

Authors

H Azeroual¹, J-L Bantignies², D Maurin², D Granier¹, J Haines¹, O Cambon¹, P Hermet¹

Affiliations

¹ ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France. patrick.hermet@umontpellier.fr.
² Laboratoire Charles Coulomb (L2C), CNRS, University of Montpellier, France.

PMID: 36880275
DOI: 10.1039/d3cp00587a

Abstract

We report the existence in NaLa(SO₄)₂·H₂O of a displacive phase transition under 200 K from the nonpolar P3₁21 to the polar P3₁ space group. This phase transition was predicted by density functional theory based calculations and experimentally confirmed from infrared spectroscopy and X-ray diffraction. The A₂ polar irreducible representation is the primary order parameter. The structural water and hydrogen bonding are the mechanism driving the phase transition. The piezoelectric properties of this new P3₁ phase have been investigated by first principles based calculations. The highest piezoelectric-strain constants in the zero Kelvin limit are predicted for the d₁₂ and d₄₁ elements with values about 3.4 pC N^-1. This compound could be interesting as piezoelectric actuator for cryogenic applications.