Theory and Simulation of Ferroic Materials

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Symmetry breaking in materials often produces emergent physical behaviour. Common examples include time-reversal symmetry breaking in (ferro)magnetics and spatial-inversion symmetry breaking in ferroelectrics, but there exists a plethora of other types. ABX3 perovskites are sometimes used as a prototypical example material in this regard, since they can undergo various types of electronic, atomic and spin orderings that break symmetry in different ways and induce new types of properties, often with potential for technological applications. This project will study these types of materials using a variety of computational and theoretical tools, including density functional theory (DFT). Several projects are available within this theme, including:- Anti-ferroelectrics (AFEs): Due to the shape of their double hysteresis loop, AFEs have potential for energy storage but they are relatively rare and understudied. This project aims to provide new fundamental perspectives towards the design of new AFEs with enhanced properties.- Dynamics and excitations of ferroics: This project will build "second principles" based atomic potentials, from DFT, in order to study phase transitions, thermal properties (such as negative thermal expansion), and topological objects (e.g. domain walls, vortices and skyrmions) in ferroics. - Complex oxide interfaces: Interfaces between or within materials can induce emergent phenomena not observed in the bulk, such as 2DEGs, hidden magnetic order, multiferroic behaviour, electric-field reversal of exchange bias, to name a few.- Exotic ferroelectrics: Typical (proper) ferroelectrics host a wide range of potential applications. This project aims to reveal new atypical types, such as relaxor, improper, triggered and hyper- ferroelectrics, which can display unusual properties potentially relevant for novel future technologies