Asteroid impacts create diamond materials with exceptionally complex structures

Asteroid impacts create diamond materials with exceptionally complex structures

asteroid

Credit: Pixabay/CC0 Public domain

According to an international study led by UCL and Hungarian scientists, shock waves caused by the collision of asteroids with Earth create materials with a range of complex carbon structures, which could be used to advance future applications. engineering.

Published today in Proceedings of the National Academy of Sciencesthe research team found that diamonds formed in a high-energy shock wave from an asteroid collision around 50,000 years ago have unique and exceptional properties, caused by the high temperatures in the short term and extreme pressure.

The researchers claim that these structures can be targeted for advanced mechanical and electronic applications, giving us the ability to design not only ultra-hard but also malleable materials with tunable electronic properties.

For the study, scientists from the UK, US, Hungary, Italy and France used detailed state-of-the-art crystallographic and spectroscopic examinations of the Canyon Diablo iron meteorite mineral lonsdaleite discovered for the first time in 1891 in the Arizona desert.

Named after the pioneering British crystallographer, Professor Dame Kathleen Lonsdale, the first female professor at UCL, lonsdaleite was previously thought to be composed of pure hexagonal diamond, which distinguished it from conventional cubic diamond. However, the team discovered that it is actually made up of nanostructured diamonds and graphene-like intergrowths (where two minerals in a crystal grow together) called diaphites. The team also identified stacking faults, or “errors” in the sequences of the repeating patterns of the atom layers.

Lead author Dr Péter Németh (Institute for Geological and Geochemical Research, RCAES) said: “Through the recognition of the different types of intergrowth between graphene and diamond structures, we can come closer to understanding pressure-temperature conditions that occur during asteroid impacts.”

The team found that the distance between layers of graphene is unusual due to the unique environments of carbon atoms occurring at the interface between diamond and graphene. They also demonstrated that the diaphite structure is responsible for a previously unexplained spectroscopic feature.

Study co-author Professor Chris Howard (UCL Physics & Astronomy) 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 microscopy.

According to the scientists, the structural units and complexity reported in lonsdaleite samples can occur in a wide range of other carbonaceous materials produced by static shock and compression or by deposition from the vapor phase.

Study co-author Professor Christoph Salzmann (UCL Chemistry) said: “Through the controlled growth of layers of structures, it should be possible to design materials that are both ultra-hard and ductile, as well as adjustable electronic properties from a conductor to an insulator.

“The discovery therefore opened the door to new carbon materials with interesting mechanical and electronic properties that could lead to new applications ranging from abrasives and electronics to nanomedicine and laser technology.”

In addition to drawing attention to the exceptional mechanical and electronic properties of the reported carbon structures, scientists are also challenging the current simplistic structural view of the mineral called lonsdaleite.

The researchers are also grateful to the late co-author, Professor Paul McMillan, who held the Sir William Ramsay Chair of Chemistry at UCL, for bringing the team together, his tireless enthusiasm for this work and his lasting contributions to the field of diamond research.


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More information:
Impact formed carbon materials with intergrowth sp3– and sp2-linked nanostructured units, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2203672119

Provided by University College London

Quote: Asteroid impacts create diamond materials with exceptionally complex structures (2022, July 19) Retrieved July 20, 2022 from https://phys.org/news/2022-07-asteroid-impacts-diamond-materials-exceptionally .html

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