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Discovering Ferro- and Piezoelectricity in Lead-Free Oxyhydrides Ln2H4O (Ln = Y, La)

submitted on 07.07.2019 and posted on 08.07.2019 by Aleksandr Pishtshev, Evgenii Strugovshchikov
One of the most significant aspects of crystal chemistry of multianionic oxyhydrides is the possibility of flexible regulation of the composition-structure-function relationships. In the context of competitive coordinations of different anions in the crystal lattice, this may afford formation of a number of stable stoichiometric phases without inversion symmetry. In the present work, we demonstrated that semiconducting yttrium and lantanium oxyhydrides with the composition Ln2H4O (Ln=Y, La) have an attractive potential for the design of novel lead-free ferro- and piezoelectric systems. By means of advanced DFT-based computational simulations we predicted that several polar monoclinic and orthorhombic phases of Ln2H4O may exhibit exceptional ferro- and piezoelectric properties as well as electromechanical coupling characteristics that are especially suitable for the piezoelectric devices working in a shear mode. Structure-dependent theoretical evaluations of the relevant physical responses demonstrated estimates of ferro- and piezoelectric characteristics that are comparable with the specifications of advanced ferroelectric solid solutions. Thus, our prediction of lead-free piezoelectric systems forms a solid and technologically reliable basis for the future development of effective and non-hazardous materials.


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Institute of Physics, University of Tartu



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Declaration of Conflict of Interest

No conflict of interest.