“This is a historic achievement,” announces a University of Rochester team led by Professor Ranga Dias after creating a superconducting material that is workable at room temperature and relatively low pressure. Their study was published this week in the journal Nature.
“With this material – nitrogen-doped lutetium hydride (NDLH) – came the dawn of superconductivity in environmental conditions and applied technologies”, highlight the authors.
With only 20.5°C and a gigapascal
“With this material (nitrogen-doped lutetium hydride) came the dawn of superconductivity in ambient conditions and applied technologies,” according to the authors.
“The most exciting finding is that we were able to observe the pressure drop by two orders of magnitude compared to our previous work, i.e. from 270 gigapascals to 1 GPa and a temperature of 69 degrees Fahrenheit (20.5 °C). Dias explains to SINC.
Although one gigapascal, which is 145,000 pounds per inch (psi), may seem like extraordinarily high pressure (sea level pressure is about 15 psi), strain engineering techniques commonly used in chip manufacturing, for For example, they incorporate materials that are held together by even greater internal chemical pressures.
One millimeter sample of lutetium hydride, the superconducting material created in the laboratory. Composite image of various microscope approaches and with color enhancement. / University of Rochester/J. adam fenster
Scientists have been chasing this breakthrough in condensed matter physics for over a century. Superconducting materials have two main properties: electrical resistance disappears and ejected magnetic fields pass around the superconducting material. In this context, the potential of new materials such as the one developed is enormous.
Improvements in power grids and nuclear fusion
For example, in the future they could allow electrical grids to transmit electricity without losing up to 200 million megawatt hours of energy that is now produced due to the resistance of wires. Also levitating and frictionless high-speed trains, more accessible medical imaging and scanning techniques, tokamak machines that use magnetic fields to confine plasmas and achieve nuclear fusion as an unlimited source of energy, and faster and more efficient electronics for digital logic and memory devices. .
We think we can grow this material at a nanoribbon scale that could be used to make chips.
Ranga Dias (U. Rochester)
“Through certain engineering tools (called stain), we believe that we can cultivate this material on a nanoribbon scale that could be used to manufacture chips”, advances Dias as one of the most accessible applications.
A previous article retracted
His team had already reported the creation of two materials (carbonaceous sulfur hydride and yttrium superhydride) that were superconductors at room temperature, but the criticisms and doubts raised by the work forced the editors of Nature to withdraw article.
The authors have made every effort to document their research and alleviate the concerns of other researchers.
Now, given the importance of the new discovery, the Rochester researchers went to great lengths to document their research and prevent the same thing from happening again, as well as presenting new data in their previous study.
The new work went through five rounds of review. Even so, independent scientists from the Chinese Academy of Sciences and the University of Illinois (USA), evaluate it in a side articlealso published in Nature, entitled: “Superconductivity at room temperature raises hope, but doubts remain”.
Nitrogen doped lutetium hydride (NDLH)
In recent years, hydrides created by combining rare earth metals with hydrogen and then adding nitrogen or carbon have given researchers a “working recipe” for creating superconducting materials at lower and lower pressures.
Lutetium seemed “a good candidate to try,” Dias says, since it has 14 electrons ideally located for superconductivity to occur at room temperature. The key question was how they were going to stabilize it to reduce the required pressure: “That’s where nitrogen comes into play,” he replies.
The material was created with a gaseous mixture of 99% hydrogen and 1% nitrogen, which was placed in a reaction chamber with a pure sample of lutetium.
This element, like carbon, has a rigid atomic structure that can be used to create a more stable, cage-like network within a material. This provides the necessary stability for superconductivity to occur at low pressure.
Dias’ team created a gaseous mixture of 99% hydrogen and 1% nitrogen, placed it in a reaction chamber with a pure sample of lutetium and let the components react for two to three days.
The resulting compound of lutetium, nitrogen and hydrogen initially had a “brilliant blue color”, according to the article, but when it was compressed in a diamond ‘anvil’ cell it produced a “stunning visual transformation”: from blue to pink in the beginning of superconductivity and then to a bright red non-superconducting metallic state.
“I was surprised to see colors with this intensity,” acknowledges Dias, “and we humorously suggested a codename for material in this state, reddmatter, like what Spock created in the popular 2009 Star Trek movie.”
According to the researcher, the possibility of training machine learning algorithms with data accumulated from experimentation in his laboratory to predict other possible superconducting materials is particularly interesting, that is, mixing thousands of possible combinations of rare earth metals, nitrogen, hydrogen and carbon.
“The path to superconducting consumer electronics, energy transfer lines, transport and significant improvements in magnetic confinement for fusion are a reality”, concludes Dias, who considers that “we are already in the modern era of superconductors”.
Nathan Dasenbrock-Gammon et al. “Evidence for near-ambient superconductivity in an N-doped lutetium hydride”. Nature2023.