Polaris, the N8 High Performance Computer, is helping scientists gain a better understanding of how natural diamonds, and synthetic versions, can be used more effectively in diamond-based technologies in a range of research and industrial applications.
A team at Newcastle University, led by Professor Patrick Briddon, has worked with De Beers to conduct quantum-level analyses of the surfaces of natural diamonds to identify and better understand how defects are formed within diamonds. Defects are an important area for research since composition and formation processes can explain much about the ‘life’ of a diamond over its geological journey. As defects are characteristic of the growth of the diamond and influence diamond colour, understanding them is also important for gaining a better insight into their appearance.
Knowledge and optimisation of these processes are key to the development of low cost, high quality materials and technologies that could be used for novel applications in the fields of electronics, computing and advanced materials science.
Prof Briddon said:
“Calculations involving surfaces of crystals are particularly challenging as the processes are complex and require accurate, quantum-chemical simulation techniques. Since an accurate model of a surface must have sufficient surface area and depth to realistically represent a real diamond surface, the number of atoms required for even the simplest model make these calculations very demanding. The very large number of simulations required to resolve these problems mean that progress could not have been made without the use of the N8 High Performance Computing facility.”
One of the defects the N8HPC helped the team gain a better understanding of was the infrared centre made up from a combination of nitrogen and hydrogen impurities clustered together in a chemically stable arrangement, a defect which has defied identification for decades. The identification of the structure and composition of this is of great importance for connections between the gemmological use of diamonds, earth sciences and materials science, and a recently appointed PhD student, sponsored by De Beers, will be building further on this work to address a wide range of defect-related problems.
Dr Philip Martineau, from De Beers, added:
“We have had excellent relationships with the team at Newcastle University and have been impressed with the expertise, enabled by N8HPC, which they have brought to bear on problems relevant to the diamond industry.”
Image to the right shows a diamond surface, showing how atoms are connected. The semi-transparent sphere is the NV centre – a gap left by the absence of a carbon atom.
Image below shows a computational model of a specific form of a diamond surface with the coloured sites indicating the different sites within the diamond as distance from the surface increases.