Asteroid impacts create diamond materials with exceptionally complex structures

The materials created by asteroids colliding with Earth could be used for advanced engineering applications, according to an international study.

Diamonds formed during a high-energy shock wave from an asteroid collision 50,000 years ago have unique and exceptional properties due to the short-term high temperatures and extreme pressure.

The researchers say that these structures can be used for advanced mechanical and electronic applications, giving us the ability to design materials that are not only hard but also flexible.

For the study, scientists from the UK, US, Hungary, Italy and France used state-of-the-art crystallographic and spectroscopic exams of the iron meteorite.

lonsdaleite was named after the first female professor at the University College London and was thought to be a pure diamond. The team found that it is composed of diamond and Graphene-like intergrowths, which are called diaphites. The team found fault in the sequence of the repeating patterns of atoms.

The pressure and temperature conditions that occur during asteroid impacts can be understood with the recognition of the various intergrowth types.

The environment of carbon atoms at the interface between diamond and Graphene made the distance between the layers unusual. The diaphite structure is responsible for a previously unknown feature.

Professor Chris Howard said, "This is very exciting since we can now detect diaphite structures in diamond using a simple spectroscopic technique without the need for expensive and laborious electron microscopes."

The structural units and the complexity reported in the lonsdaleite samples can be found in a wide range of other carbonaceous materials.

The co-author of the study said that it should be possible to design materials that are both hard and soft.

The discovery has opened the door to new carbon materials with exciting mechanical and electronic properties that may result in new applications.

As well as drawing attention to the exceptional mechanical and electronic properties of the carbon structures, the scientists challenge the simplistic structural view of the mineral.

The late co-author Professor Paul McMillan, who was the Sir William Ramsay Chair of Chemistry at the University College London, brought the team together, his enthusiasm for this work and his lasting contributions to the field of diamond research.

More information: Shock-formed carbon materials with intergrown sp³- and sp²-bonded nanostructured units, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2203672119 Journal information: Proceedings of the National Academy of Sciences