The breakthrough could one day transform technologies that use electric energy, but it comes from a team facing doubts after a retracted paper on superconductors.
 
A small diamond sits under a microscope atop an anvil cell in a gold-colored housing.
A diamond, placed in a diamond anvil cell under a microscope, for use in superconductivity experiments in a University of Rochester lab led by Ranga P. Dias.Credit...Lauren Petracca for The New York Times

New Room-Temperature Superconductor Offers Tantalizing Possibilities

The breakthrough could one day transform technologies that use electric energy, but it comes from a team facing doubts after a retracted paper on superconductors.

By Kenneth Chang

As part of the reporting for this story, Kenneth Chang visited a laboratory at the University of Rochester in New York where new superconducting materials are studied.
 

Scientists announced this week a tantalizing advance toward the dream of a material that could effortlessly convey electricity in everyday conditions. Such a breakthrough could transform almost any technology that uses electric energy, opening new possibilities for your phone, magnetically levitating trains and future fusion power plants.

Usually, the flow of electricity encounters resistance as it moves through wires, almost like a form of friction, and some energy is lost as heat. A century ago, physicists discovered materials, now called superconductors, where the electrical resistance seemingly magically disappeared. But these materials only lost their resistance at unearthly, ultracold temperatures, which limited practical applications. For decades, scientists have sought superconductors that work at room temperatures.

This week’s announcement is the latest attempt in that effort, but it comes from a team that faces wide skepticism because a 2020 paper that described a promising but less practical superconducting material was retracted after other scientists questioned some of the data.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 little bit of nitrogen mixed in. It needs to be compressed to a pressure of 145,000 pounds per square inch before it gains its superconducting prowess. That is about 10 times the pressure that is exerted at the bottom of the ocean’s deepest trenches.

 

But it is also less than one one-hundredth of what the 2020 result required, which was akin to the crushing forces found several thousand miles deep within the Earth. That suggests that further investigations of the material could lead to a superconductor that works at ambient room temperatures and at the usual atmospheric pressure of 14.7 pounds per square inch.

“This is the start of the 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, said to a room packed full of scientists on Tuesday at a meeting of the American Physical Society in Las Vegas.

A fuller accounting of his team’s findings was published on Wednesday in the Nature, the same journal that published, then retracted the 2020 findings.

 Ranga Dias stands smiling with his arms crossed in front of a chalkboard with various drawings and numbers and equations in multicolored chalk. He is wearing a blue sweatshirt and wears eyeglasses.
Ranga P. Dias, a professor of mechanical engineering and physics at the University of Rochester in New York.Credit...Lauren Petracca for The New York Times



The team at Rochester started with a small, thin foil of lutetium, a silvery white metal that is among the rarest of rare earth elements, and pressed it between two interlocking diamonds. A gas of 99 percent hydrogen and 1 percent nitrogen was then pumped into the tiny chamber and squeezed to high pressures. The sample was heated overnight at 150 degrees Fahrenheit, and after 24 hours, the pressure was released.
 

About one-third of the time, the process produced the desired result: a small vibrant blue crystal. “Doping nitrogen into lutetium hydride is not that easy,” Dr. Dias said.

In one of the University of Rochester laboratory rooms used by Dr. Dias’s group, Hiranya Pasan, a graduate student, demonstrated the surprising hue-changing property of the material during a reporter’s visit last week. As screws tightened to ratchet up the pressure, the blue turned into a blushing tint.

“It is very pink,” Dr. Dias said. With even higher pressures, he said, “it goes to a bright red.”

Shining a laser through the crystals revealed how they vibrate and unlocked information about the structure.

In another room, other members of Dr. Dias’s team were making magnetic measurements on other crystals. As the temperatures dropped, the expected squiggles appeared in the data plotted on a computer screen, indicating a transition to a superconductor.

“This is a live measurement we’re doing right now,” Dr. Dias said.

In the paper, the researchers reported that the pink crystals exhibited key properties of superconductors, like zero resistance, at temperatures up to 70 degrees Fahrenheit.

“I’m cautiously optimistic,” said Timothy Strobel, a scientist at the Carnegie Institution for Science in Washington who was not involved in Dr. Dias’s study. “The data in the paper, it looks great.”