Dr Nicholas Bristowe

Research summary

Perovskites and related frameworks are often put forward as prototypical example of functional materials since small changes in chemistry, atomic structure, strain or applied fields can tune or switch the physical behaviour of the material in a way which could be useful for various types of devices. We study structure-property relationships in these kinds of systems since phase transitions arising from just small atomic distortions, can have a large influence on physical properties. We are not only interested in the bulk, but also structure-property relationship that can exist at interfaces (e.g. heteroepitaxial, or domain walls) or surfaces. Often it is highly desirable to turn to a theoretical tool which does not rely on experimental parameterisation. For example, when designing new materials which have yet to be made, when exploring phase space of a material which has yet to be studied, or when attempting to unravel the underlying mechanisms behind unexpected observations. Density functional theory (DFT) is now a computationally affordable method to study the ground state of even fairly complex materials at the microscale. When properties associated with processes occurring at the mesoscale are required (e.g. dynamical properties or domain wall evolution), DFT can be used to parameterise classical atomic potentials.

Overview:

• Emergent phenomena at interfaces and surfaces
• (Multi)ferroic perovskites and related materials
• DFT, atomic potential and phenomenological modelling

Keywords

Elastic Properties, Jahn-Teller, Metal-Oxide Interfaces, Phase Transitions, Nanostructures, Photovoltaics, Thin Films, Free Energy, Ab Initio M.D., Linear-Scaling DFT, Structure Prediction, Lattice dynamics

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