Diamonds are on to have a new best friend.
Prized by jewelers for their tough exterior and sparkling interior, engineers also appreciate them for their electronic properties. Now, scientists have found a way to cultivate diamonds in the lab that can be stressed and strained – without losing their shape – to give them special electrical conduction properties.
A a hundred times thinner than a human hair, these stretch diamonds can fold up to 10 percent its original shape before bouncing back – all at a gentle room temperature.
Why is this important – In addition to being resistant, diamonds are very conductive in terms of electricity and heat. By creating stretchable diamonds in the lab, scientists hope to improve these features and integrate them into next-generation electronics, including quantum computer chips.
Their findings were published Thursday in the journal Science.
Here’s the background – When it comes to designing electronic components that are smaller, faster and more efficient than their silicon-based counterparts, diamond-based materials are “Mount Everest” from an engineer – beautiful in theory, but extremely difficult in practice.
Part of the problem, the authors explain, is overcoming the limitations of the material’s crystal structure, as well as optimizing its “merit figures“- ironically, the characteristics that make it a good match for these future electronic systems.
Ju Li, co-author of the study and professor of materials science and engineering at the Massachusetts Institute of Technology, recounts Reverse these properties “change dramatically” with the “band gap” of the material, which is a measure of energy.
“The bandgap is a practical indicator of the extent to which the physical properties of a well-known material can change with elastic deformation,” Li says.
Li’s team set out to find out if the pressure on diamonds could change – and even further improve – those merit numbers, without the diamonds breaking or resisting the strain.
“This is an active area of research,” Li says.[But] constraint engineering can be very powerful. “
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In their new work, the researchers set out to test how well they could lift monocrystalline diamonds grown in their lab using what’s called a nanoindenter – essentially, a microscopic ram.
What did they do – The team made several diamond samples in the lab and used their little ram to see how they would react to different levels of voltage coming from different angles. They then used transmission electron microscopy to examine the crystal structure of the diamonds and see how they were altered by the assault.
What they discovered – After subjecting their tiny crystals to a fair amount of poking and pushing, the researchers found that they could reliably achieve between 6.5 and 8.2 percent strain with full recovery of form when pushed from three different directions. Overall, they observed a maximum deformation of 9.7 percent, which, according to the authors, is very close to the ideal elastic limit for a material like this.
Oddly enough, they found an increase in pressure on these diamonds resulting in a corresponding decrease in internal energy – turning them into a direct bandgap superconductor – a characteristic which will ultimately play an important role in allowing the integration of these materials into microelectronic mechanical systems, including light or quantum electronics.
And after – Microelectronics based on these curved diamonds won’t be ready for prime time anytime soon, but the researchers believe the results of their paper demonstrate that diamonds could usher in the transformation of how these electronics are made – and how quickly they become available to consumers. .
“Diamond is one of the most promising materials for high-frequency and high-power electronic devices, as well as for photonic applications,” Li says. “It is also an important quantum material.”
Instead of silicon-based computer chips, quantum computers can have diamond chips instead, which would improve their thermal conductivity and their ability to operate at temperatures above absolute zero – a notorious sticking point for technologies. quantum.
Going forward, Li says the team plans to study how this technology could also be applied to renewables and storage.
Abstract: Diamond is not only the hardest material in nature, but it is also an extreme electronic material with an ultra-wide bandgap, exceptional carrier mobilities and thermal conductivity. The tension diamond can push extreme figures of merit for device applications. We microfabricated single crystal diamond bridge structures with ~ 1 micrometer in length by ~ 100 nanometers in width and obtained uniform elastic strains at sample scale under uniaxial tensile load along the directions and at room temperature . We have also demonstrated a deep elastic deformation of diamond micro-bridge networks. Ultra-large and highly controllable elastic strains can fundamentally alter the loose band structures of diamond, including a substantial calculated band gap reduction down to ~ 2 electron volts. Our demonstration highlights the immense application potential of deep elastic strain engineering for photonics, electronics and quantum information technologies.