Lattice models of 2D domain texture in ferroelectric perovskites
This is a fully-funded 4-year PhD position based in the HetSys Centre for Doctoral Training at the University of Warwick.
Project outline
Ferroelectric perovskites are promising materials for device applications due to rich topological aspects to their polarisation domain structure. This mesoscale structure can be controlled with strain engineering.
The relationship between crystal structure, strain and local polarisation can be understood at the length scale of a few repeat units of the crystal structure. However, to predict and ultimately design domain structure we need effective models on much larger length scales.
This project will develop exactly this capability, building minimal on-lattice models to capture the essential physics and parameterise/validate these via analysis of experimentally obtained images.
Supervisors
Primary: Dr Mark Senn (Chemistry)
Prof. David Quigley (Physics)
The aim of the project is to build, parameterise and validate a mesoscopic (length scales of micrometres) model of domain texture. In such a model the individual elements are vectors which represent the polarisation of each crystallographic unit in the material. This will involve developing a skillset which includes the following.
- Building model Hamiltonians which obey relevant symmetries and capture important interactions.
- Robust research software engineering to implement (essentially from scratch) these models and simulate them.
- Characterise domain textures from both the model and from experimental data gathered by other researchers.
- Building expertise in thermodynamic perturbation theory to fine tune models.
- Rigorous uncertainty quantification for predicted domain structures, obtained by parameterising ensembles of models.
The principle outcome will be a software tool for parameterising and simulating the domain texture model. This will be released as a properly documented and tested package developed to the highest standards of research software engineering.
We then hope to apply this tool to tackle some or all of the following challenges, each of which has the potential to generate publications in collaboration with experimentalist colleagues.
- Origin of ferroelectric domain and strain textures arising from quasi U1 symmetry in hexagonal Barium Titanate
- Understanding the control parameter for complex ferroelastic domain structure in high-Tc cuprates, and implication for filamentary superconductivity
- Interplay between ferroelastic domain structures and electronic phase separation in the colossal magnetoresistance manganites
These are all challenging problems key to unlocking the potential of these functional materials for applications in future electronic devices.
The student will acquire skills in theoretical physics, probability, computational statistical mechanics, data driven modelling and synthesis of existing literature. They will learn to process and characterise large data sets using machine learning, and how to understand and quantify the limitations of models and data.
Software development will likely involve a mixture of Python (for interoperability) and C (for performance). The student will learn how to link these together. GPU programming in CUDA will likely form part of this, allowing for thousands for realisations of the model to be simulated concurrently to generate sufficient statistical data.
These skills position you for careers in AI research, computational materials science, national laboratories, tech industry or academic research. The HetSys training provides a foundation for these skills through dedicated courses and cohort activities.
We require at least a II(i) honours degree at BSc or an integrated masters degree (e.g. MPhys, MChem, MSci, MEng etc.) in a physical sciences, mathematics or engineering discipline. We do not accept applications from existing PhD holders.
If you are an overseas candidate please check here that you hold the equivalent grades before applying.
For postgraduate study in HetSys, the term “overseas” or “international” student refers to anyone who does not qualify for UK home fee status. This includes applicants from the European Union (EU), European Economic Area (EEA), and Switzerland, unless they hold settled or pre-settled status under the UK’s EU Settlement Scheme.
If you are a European applicant without UK residency or immigration status that qualifies you for home fees, you will be classified as an overseas student.