Quantum-fluctuation-stabilized orthorhombic ferroelectric ground state in lead-free piezoelectric (Ba, Ca)(Zr, Ti)O-3

Akbarzadeh, Alireza and Brajesh, Kumar and Nahas, Yousra and Kumar, Naveen and Prokhorenko, Sergei and Swain, Diptikanta and Prosandeev, Sergey and Walter, Raymond and Kornev, Igor and Iniguez, Jorge and Dkhil, Brahim and Ranjan, Rajeev and Bellaiche, L (2018) Quantum-fluctuation-stabilized orthorhombic ferroelectric ground state in lead-free piezoelectric (Ba, Ca)(Zr, Ti)O-3. In: PHYSICAL REVIEW B, 98 (10).

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Abstract

We numerically investigate the phase diagram of the giant-piezoelectric (1 - x)Ba(Zr0.2TiO0.8)O-3-x(Ba0.7Ca0.3)TiO3 system, treating the ions either as classical objects (via classical Monte Carlo or CMC simulations) or quantum mechanically (via path-integral quantum Monte Carlo or PI-QMC simulations). It is found that PI-QMC not only provides a better agreement with available experimental data for the temperature-composition phase diagram, but also leads to the existence of an orthorhombic ground state in a narrow range of composition, unlike CMC that ``only'' yields ground states of rhombohedral or tetragonal symmetry. X-ray powder diffraction experiments are further conducted at 20 K. They confirm the occurrence of a quantum-fluctuation-induced orthorhombic state for some compositions and therefore validate the PI-QMC prediction. The role of quantum effects on the local structure, such as the annihilation of a homogeneous rhombohedral system in favor of an inhomogeneous mixing of orthorhombic and rhombohedral clusters, is also documented and discussed.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW B
Publisher:	AMER PHYSICAL SOC
Additional Information:	Copy right for this article belong to AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	15 Sep 2018 15:50
Last Modified:	15 Sep 2018 15:50
URI:	http://eprints.iisc.ac.in/id/eprint/60682

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