Polarisation patterns in nanoscale ferroelectrics for low-power nano-electronics

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By analogy with ferromagnets that have a spontaneous magnetisation, ferroelectrics are materials with a spontaneous electrical polarization that can be switched by an applied electric field. While ferroelectrics already have many well-established applications that exploit their superior piezoelectric, pyroelectric and dielectric properties, they are also actively studied as leading materials for the memory, transistors and memristive components in next generation low-power electronics and neuromorphic computing. These applications require ferroelectrics with dimensions at the nanoscale, where their properties change dramatically.At nanoscale, ferroelectrics exhibit complex exotic polarisation patterns with interesting topologies. Nanoscale ferroelectric domains are extremely responsive to external stimuli, leading to dramatic enhancements in dielectric properties. Perhaps even more excitingly, the domains walls, which locally break the symmetry of the bulk material, can host properties that are distinct from those of the domains that they separate, allowing them to act as functional entities in their own right. Our ability to create and destroy domains at will with electric fields makes them ideal for reconfigurable electronics, overturning the classic idea that our electronic circuits need to consist of fixed hardware components and leading to the emergence of the field of domain wall nanoelectronics.However, to harness their true potential there is a great deal of fundamental physics yet to uncover. As domain walls are usually only a few atoms thick and highly dynamic, it is essential to characterise them at the relevant spatial and temporal scale.This project will aim to investigate the physics of complex nanoscale polarisation patterns in ferroelectricthin films and superlattices, including their structure, response to applied stimuli and their effect on the functional properties of these materials.