WASHINGTON — American researchers reported in this week’s Applied Physics Letters their new recipe for a powerful plated metal combination that superconducts at easily attained temperatures.
The findings could pave the road for the next critical steps in the development of cutting-edge supercomputers.
They developed an ultrathin layer of rhenium sandwiched between layers of gold, each measuring 1/1000th the diameter of a human hair that can superconduct at critical temperature over 6 Kelvin, higher than usual ones.
“The sheer magnitude of the critical temperature was unexpected,” said Don David, director of the Cooperative Institute for Research in Environmental Sciences and the paper’s co-author. “We were surprised at how robust and effective the thin layer of electroplated Re was.”
A superconductor is a material with zero electrical resistance when cooled to a critical temperature. The temperature is usually strikingly low and expensive to obtain.
The team’s electroplated rhenium meets ideal characteristics desired for use in circuit boards for ultrafast, next-generation computing applications: superconducting at higher, easier-to-achieve critical temperatures, easy to work with mechanically, non-toxic, and melts at high temperatures.
Electroplating is a process passing an electrical current through an aqueous solution of a dissolved metal to create a metal coating on a submerged object.
They chose rhenium, a hard, trace metal, with a high melting point, often used in the construction of jet engine turbines. It superconducts up to 6K, well above the boiling temperature of liquid helium (4.2 K).
The researchers said that being able to electroplate a superconductor was a giant step forward in the creation of tomorrow’s high-performance, superconducting computers.
Inside every computer there is a circuit board: a layered, electronic plank etched with thousands of conductive pathways. Pulses of electrical information called “bits” speed across the board, carrying out the computer’s functions.
In regular computers, these electrical pulses are hindered by the material that comprises the board, so that electrical resistance slows down the electrons scurrying about the circuitry, and the wasted energy becomes heat.
But with a superconductor, there is literally zero electrical resistance, so there is no heating. This efficiency will result in exceedingly fast and powerful computer systems.
The new finding is presenting evidence that electroplated rhenium may be the best material found to date for superconductive computer circuit board construction.
Many other superconductive materials, like mercury or lead, are difficult to work with mechanically, have poor soldering properties, or melt at too-low temperatures.
Even more impressively, the electroplating process would be easily scaled-up to mass-production, David said.