Superconductors that could effortlessly transmit electricity

Scientists recently announced a tantalizing advance toward the dream of a material that could effortlessly transmit electricity under everyday conditions. Such a breakthrough could transform almost any technology that uses electrical power, opening up new possibilities for your phone, for magnetically levitating trains, and for future fusion power plants.

Typically, the flow of electricity encounters resistance as it moves through the wires, almost like a form of friction, and some of the energy is lost in the form of heat. A century ago, physicists discovered materials, now called superconductors, where electrical resistance seemed to magically disappear. But these materials only lost their strength at ultracold and out-of-this-world temperatures, limiting practical applications. For decades, scientists have searched for superconductors that work at room temperature.

The announcement is the latest attempt in that effort, but it comes from a team facing widespread skepticism that a 2020 study describing a promising but less practical superconducting material was retracted after other scientists questioned some of the data.

The new superconductor consists of lutetium, a rare-earth metal, and hydrogen with a bit of nitrogen mixed in. It must be compressed to a pressure about 10 times greater than at the bottom of the deepest trenches in the ocean.

But it’s less than one-hundredth of the pressure the 2020 result required, which was similar to the crushing forces found thousands of kilometers deep on Earth. That suggests that further research could lead to a superconductor that works at room temperature and normal atmospheric pressure.

“This is the start of a new type of material that is useful for practical applications,” Ranga P. Dias, a professor of mechanical engineering and physics at the University of Rochester in New York, told scientists March 7 at a meeting. from the American Physical Society in Las Vegas.

A fuller report of the findings was published on March 8 in Nature, the journal that released and then retracted the 2020 findings.

The team started with a thin sheet of lutetium, a silvery-white metal that is listed among the rarest rare-earth elements, and pressed it between two diamonds. A 99 percent hydrogen and 1 percent nitrogen gas was pumped into the chamber and compressed at high pressures. The sample was heated overnight to 65 degrees Celsius and after 24 hours the pressure was released.

About a third of the time, the process produced the desired result: a small, vibrant blue crystal.

In one of the lab rooms used by Dias’s group, graduate student Hiranya Pasan demonstrated the hue-shifting property of the material. When the screws were tightened to increase the pressure, the blue turned into a blush tint. “It’s very pink,” Dias said. With even higher pressures, she said, it “turns bright red.”

Passing a laser through the crystals revealed how they vibrate and information about their structure.

In the paper, the researchers said the pink crystals exhibited key superconducting properties, such as zero resistance, at temperatures up to 21 degrees.

“I’m cautiously optimistic,” said Timothy Strobel of the Carnegie Institute of Science in Washington, who was not involved in the Dias study.

“If this is real, it’s a really important breakthrough,” said Paul CW Chu, a professor of physics at the University of Houston, in Texas, who was not involved in the research.

However, the “if” part of that sentiment revolves around Dias, who has been the subject of doubt and criticism. The results of the 2020 Nature study have yet to be replicated by other groups, and critics say Dias has been slow to let others examine his data.

The new article went through the peer review process in the same journal.

Strobel acknowledged the continuing controversy surrounding Dias. “I don’t want to jump to too many conclusions, but there could be a pattern of behavior here,” Strobel said. “He really could be the best high-pressure physicist in the world, next to win the Nobel Prize. Or something else happens.”