A team of physicists two years ago discovered a material capable of room-temperature superconductivity, making international headlines. The same team, from the University of Nevada at Las Vegas, has reproduced that accomplishment, this time at the lowest pressure ever recorded.
This means that science is closer than it’s ever been to a practical, replicable material that could one day revolutionize how energy is transported.
To achieve their 2020 triumph, the scientists chemically synthesized a mix of carbon, sulfur, and hydrogen first into a metallic state, called carbonaceous sulfur hydride, and then even further into a room-temperature superconducting state using extreme pressure — 267 gigapascals — conditions you’d only find in nature near the center of the Earth. Now, team, UNLV physicist Ashkan Salamat and colleague Ranga Dias, a physicist with the University of Rochester, can complete the feat at just 91 GPa — roughly one-third the pressure initially reported.
Consistently Lower Pressures
A diamond anvil cell, a research device used to lower the pressure needed to observe a material capable of room-temperature superconductivity. Credit: NEXCL
A room-temperature superconductor is a material that is capable of achieving superconductivity at operating temperatures above 0 °C (32 °F), in other words, temperatures that can be reached and easily maintained in an everyday environment.
Through intricate tuning of the composition of carbon, sulfur, and hydrogen used in the original breakthrough, scientists can create material at a lower pressure that retains its state of superconductivity.
“These are pressures at a level difficult to comprehend and evaluate outside of the lab, but our current trajectory shows that it’s possible achieve relatively high superconducting temperatures at consistently lower pressures—which is our ultimate goal. At the end of the day, if we want to make devices beneficial to societal needs, then we have to reduce the pressure needed to create them,”
lead author Gregory Alexander Smith said.
The pressures are still extremely high — about a thousand times higher than you’d see at the bottom of the Pacific Ocean’s Mariana Trench — they are still race toward a goal of near-zero. It’s a marathon that’s gaining steam at UNLV as scientists gain a better understanding of the chemical relationship between the carbon, sulfur, and hydrogen that make up the material.
“Our knowledge of the relationship between carbon and sulfur is advancing rapidly, and we’re finding ratios that lead to remarkably different, and more efficient, responses than what was initially observed. To observe such different phenomena in a similar system just shows the richness of Mother Nature. There’s so much more to understand, and every new advancement brings us closer to the precipice of everyday superconducting devices,”
said Salamat, who directs UNLV’s Nevada Extreme Conditions Lab (NEXCL) and contributed to the latest study.
The Energy Efficiency Dream
Superconductivity is a remarkable phenomenon first observed more than a century ago, but only at unusually low temperatures that preempted any thought of practical application. Only in the 1960s did scientists theorize the feat might be possible at higher temperatures.
Why did the 2020 discovery by Salamat and colleagues of a room-temperature superconductor excited the science world so much? Partly because the technology supports electrical flow with zero resistance, meaning that energy passing through a circuit could be conducted infinitely and without loss of power.
It could have significant implications for energy storage and transmission, from better cell phone batteries to a more efficient energy grid. According to Salamat, the properties of superconductors can support a new generation of materials that could fundamentally change the energy infrastructure of the U.S. and beyond.
“Imagine harnessing energy in Nevada and sending it across the country without any energy loss. This technology could one day make it possible,”
he said.
