Newly Discovered Form of Carbon Is Harder Than Diamond

A team of researchers at North Carolina State University is manipulating carbon in intriguing ways. They created a third form (or phase) of solid carbon, called Q-carbon, that glows when exposed to low levels of energy and is harder than diamond. They also developed a technique that can turn the Q-carbon into "diamond-related structures" without high temperatures and pressure. Their findings were published in recent issues of the Journal of Applied Physics and APL Materials.

They created the Q-carbon by coating a substrate like sapphire or glass with elemental carbon, which unlike graphite or diamond—the two known forms of solid carbon—does not have a regular, well-defined crystalline structure. They blasted the carbon with a single laser pulse for 200 nanoseconds while simultaneously heating it to a scorching 3727°C, then rapidly cooling it.

The resulting Q-carbon is unique among solid carbons in that it is ferromagnetic, which means that like iron, cobalt, and nickel, it retains its magnetism even after a magnetic field has been removed. In a press statement, lead author Jay Narayan said the researchers hadn't thought it was even possible for Q-carbon to be ferromagnetic. He added that the strength of Q-carbon and its low work-function, or "willingness to release electrons," could make it useful in the realm of electronic display tech. If this unusual material is found in the natural world, Narayan said, it's "possibly in the core of some planets."

So far, the scientists have found that they can produce Q-carbon film to be between 20 nanometers and 500 nanometers thick, and by changing the rate at which the carbon is cooled, they can create diamond-like structures within the form of solid carbon. "We can create diamond nanoneedles or microneedles, nanodots, or large-area diamond films," Narayan said; all have potential uses in electronics and other applications. “And it is all done at room temperature and at ambient atmosphere.… So, not only does this allow us to develop new applications, but the process itself is relatively inexpensive."

The researchers have filed provisional patents for both Q-carbon and the technique that produces the diamond structures.