Mesoscopic electric field predictions and specimen shape measurements to improve reconstruction in atom probe tomography

Atom probe tomography is a microscopy and microanalysis technique that can map the distribution of each element in small volume of a material with near-atomic precision. A new facility at Imperial College London is being set up to allow for facile transfer, under controlled atmosphere, of specimens from the atom probe into a transmission electron microscope, allowing for precise imaging of atom probe specimens, which sharp needles below 100 nanometres across. In the analysis of complex devices, typically multilayer stacks, the specimen can develop complex shapes that affect the spatial precision of the data reconstruction.

This project will build on a collaboration with the University of Oxford to perform both interrupted atom probe experiments to acquire specimen shapes by electron microscopy and feed these into a mesoscopic model to improve reconstruction protocols, and correlate structure-composition and activity on materials for energy application. We will combine these models with experimental measurements of specimen shape on thin films of materials for energy applications, imaged by transmission-electron microscopy at different stages of the analysis.

The developed model is not linked or embedded with the instrument provided by CAMECA, so it will not provide a competitive advance to CAMECA as this is mostly for academic use.

The production and processing of materials accounts for 15% of UK GDP and generates exports valued at £50bn annually, with UK materials related industries having a turnover of £197bn/year. It is, therefore, clear that the success of the UK economy is linked to the success of high value materials manufacturing, spanning a broad range of industrial sectors. In order to remain competitive and innovate in these sectors it is necessary to understand fundamental properties and critical processes at a range of length scales and dynamically and link these to the materials' performance. It is in this underpinning space that the CDT-ACM fits.

The impact of the CDT will be wide reaching, encompassing all organisations who research, manufacture or use advanced materials in sectors ranging from energy and transport to healthcare and the environment. Industry will benefit from the supply of highly skilled research scientists and engineers with the training necessary to advance materials development in all of these crucial areas. UK and international research facilities (Diamond, ISIS, ILL etc.) will benefit greatly from the supply of trained researchers who have both in-depth knowledge of advanced characterisation techniques and a broad understanding of materials and their properties. UK academia will benefit from a pipeline of researchers trained in state-of the art techniques in world leading research groups, who will be in prime positions to win prestigious fellowships and lectureships. From a broader perspective, society in general will benefit from the range of planned outreach activities, such as the Mary Rose Trust, the Royal Society Summer Exhibition and visits to schools. These activities will both inform the general public and inspire the next generation of scientists.

The cohort based training offered by the CDT-ACM will provide the next generation of research scientists and engineers who will pioneer new research techniques, design new multi-instrument workflows and advance our knowledge in diverse fields. We will produce 70 highly qualified and skilled researchers who will support the development of new technologies, in for instance the field of electric vehicles, an area of direct relevance to the UK industrial impact strategy.
In summary, the CDT will address a skills gap that has arisen through the rapid development of new characterisation techniques; therefore, it will have a positive impact on industry, research facilities and academia and, consequently, wider society by consolidating and strengthening UK leadership in this field.