The Room Temperature Superconductor at Near-Ambient Conditions

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Image: A tiny lump of lutetium hydride, a new material that a team of scientists claim can be a superconductor at room temperature under relatively low pressure - University of Rochester photo / J. Adam Fenster

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In early March, 2023 an astonishing claim was made. Few discoveries in science would revolutionize technology as much as a material that achieves superconductivity at room temperature, under relatively mild pressures. However the claim is extremely controversial and does not seem to be easy to replicate, raising some doubts.

A team of physicists led by Ranga Dias, a physicist from the University of Rochester in New York says they have now demonstrated that a rare earth metal called lutetium combined with hydrogen and nitrogen can conduct electricity without resistance at 21 degrees Celsius (70 degrees Fahrenheit) and around just 10,000 atmospheres of pressure, the team reports (paper dated March 8th, 2023).

The so-called "Reddmatter" shows evidence of room temperature superconductivity.

Are we on the verge of a materials breakthrough or is this yet another fall signal?

• Being able to carry electrical current with no electrical resistance, superconductors have a wide range of applications.

• But practical devices that use superconducting components, such as the magnets in magnetic resonance imaging machines, must be chilled to ultralow temperatures to ensure the material superconducts.

• Condensed-matter physicists have therefore long hoped to develop materials that superconduct at room temperature, which would slash the costs of operating such devices.

New Room-Temperature Superconductor Offers Tantalizing Possibilities

But what if? What if this is legit? If Ranga Dias of the University of Rochester, New York, and his team have observed room-temperature (294 K), near-ambient pressure superconductivity, their discovery could rank among the greatest scientific advances of the 21st century.

• For many years, the materials with the highest superconducting transition temperatures were the copper-oxide-based “cuprates”, which superconduct when cooled to below around –130 °C at ambient pressure.

• But then in 2015 Mikhail Eremets and colleagues at the Max Planck Institute for Chemistry and the Johannes Gutenberg University Mainz, both in Germany, observed superconductivity at –70 °C in a sample of hydrogen sulphide albeit at pressures of about 150 GPa.

If confirmed by other researchers, this would be a huge breakthrough in creating devices that don't waste energy on heat when producing a current. Early signs that I have read, have not been able to replicate it.

The problem is Dias does not have a stellar track record. In October 2020, Dias and colleagues claimed in the journal Nature to have discovered superconductivity at a balmy 15 °C in a hydrogen sulphide material. The superconductor in question was made by adding carbon to hydrogen sulphide and then squeezing the sample to 220 GPa. Dias’s team found a maximum superconducting temperature of 15 °C occurring at about 260 GPa. Concerns were raised over the finding, however, and the paper was subsequently retracted in September 2022 by editors at Nature.

Researchers have not only raised the temperature, but also lowered the pressure required to achieve superconductivity.

Now, Dias and colleagues are back with a new material and one that superconducts at room temperature under less pressure than previous efforts. Dias’s team created it from a gaseous mixture of 99% hydrogen and 1% nitrogen that was place in a reaction chamber with a pure sample of lutetium. The components were left to react for a couple of days at about 200 °C.

The resulting lutetium-nitrogen-hydrogen compound was initially a blue colour. But the sample then turned pink as it was squeezed under pressure, with its change of colour coinciding with the onset of superconductivity at a temperature of –102 °C and pressure of 0.5 GPa.

It’s truly astonishing if this passes and turns out to be true.