First-principles study of structural instabilities in halide-based perovskites: Competition between ferroelectricity and ferroelasticity

First-principles study of structural instabilities in halide-based perovskites: Competition between ferroelectricity and ferroelasticity.

Atomic structure of metal-halide perovskites from first principles

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CH3NH3PbI3 perovskites: Ferroelasticity revealed

Ferroelectricity has been proposed as a plausible mechanism to explain the high photovoltaic conversion efficiency in organic-inorganic perovskites; however, convincing experimental evidence in support of this hypothesis is still missing. Identifying and distinguishing ferroelectricity from other properties, such as piezoelectricity, ferroelasticity, etc., is typically nontrivial because these ...

First - principles theory of structural phase transitions for perovskites : competing instabilities

We extend our previous first-principles theory for perovskite ferroelectric phase transitions to treat also antiferrodistortive phase transitions. Our approach involves construction of a model Hamiltonian from a Taylor expansion, first-principles calculations to determine expansion parameters, and Monte Carlo simulations to study the resulting system. We apply this approach to three cubic perov...

Competing structural instabilities in cubic perovskites.

We study the antiferrodistortive instability and its interaction with ferroelectricity in cubic perovskite compounds. Our first-principles calculations show that coexistence of both instabilities is very common. We develop a firstprinciples scheme to study the thermodynamics of these compounds when both instabilities are present, and apply it to SrTiO3. We find that increased pressure enhances ...