The smell of acrid metal fills the air as Takashi Taniguchi reaches into the core of one of the world’s most powerful hydraulic presses. This seven-metre-tall machine can squeeze carbon into diamonds — but they aren’t on its menu today. Instead, Taniguchi and his colleague Kenji Watanabe are using it to grow some of the most desired gems in the world of physics.
For the past eight days, two steel anvils have been crushing a powdery mix of compounds inside the press at temperatures of more than 1,500 °C and up to 40,000 times atmospheric pressure. Now, Taniguchi has opened the machine and cooling water is dribbling from its innards. He plucks out the dripping prize, a 7-centimetre-wide cylinder, and starts chipping at its outer layers with a knife to get rid of the waste metal that had helped to regulate the pressures and temperatures. “The last steps are like cooking,” he says, focusing intently on his tools. Eventually, he reveals a molybdenum capsule not much bigger than a thimble. He puts it in a vice and grasps it with a wrench the size of his forearm. With one twist, the capsule fractures and releases a burst of excess powder into the air. Still embedded inside the capsule are glimmering, clear, millimetre-sized crystals known as hexagonal boron nitride (hBN).
Materials laboratories all over the world want what Taniguchi and Watanabe are making here at the Extreme Technology Laboratory, a building on the leafy campus of the National Institute of Materials Science (NIMS) in Tsukuba, outside Tokyo. For the past decade, the Japanese pair have been the world’s premier creators and suppliers of ultra-pure hBN, which they post to hundreds of research groups at no charge.
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