The search for a truly room temperature superconducting material has been one of the great holy grails of engineering and physics. The ability to move electricity from point A to point B with zero resistance and therefore lossless would be a turning point for human civilization. Unfortunately, until now, every known superconductor still required very low temperatures. Today, scientists announced they have achieved superconducting at 59 degrees Fahrenheit / 15 Celsius. Even if it’s still a bit chilly, you can hit 59F in a well-conditioned building. This is a real breakthrough, but it doesn’t immediately pave the way for an easy implementation of the technology.
At extremely low temperatures, the behavior of electrons through a material changes. At temperatures close to absolute zero, electrons passing through a material form so-called Cooper pairs. Normally, individual electrons essentially ping-pong through the ion lattice of the material they are passing through. Each time an electron collides with an ion in the lattice, it loses a small amount of energy. This loss is what we call resistance. When cooled to a low enough temperature, electrons behave remarkably differently. Cooper pairs behave like a superfluid, which means they can flow through the material without any loss of underlying energy. Tests have shown that the current stored within a superconductor will remain there as long as the material remains in a superconducting state with zero energy loss.
There are still two problems that separate us from a more effective exploitation of this discovery. First, we’re not sure exactly why this combination of elements works in the first place. The research team used sulfur and carbon, then added hydrogen, forming hydrogen sulfide (H.2S) and methane (CH4). These chemicals were placed on a diamond anvil and compressed, then exposed to a green laser for several hours to break the sulfur-sulfur bonds. This is well known. Unfortunately, the determination of the exact composition of the material has so far proved impossible. The diamond anvil prevents the use of X-rays, and existing technologies that can get around this problem are unable to locate the hydrogen atoms in a lattice. The team’s efforts to characterize and understand their discovery are still ongoing.
The researchers also have a second pressing problem: it takes about 2.5 million atmospheres of pressure to create the superconducting effect. This is about 75 percent of the pressure found in the center of the Earth and is somewhat difficult to replicate on planet Earth. If we were on Jupiter, we would have far fewer problems with duplicating this kind of pressure, but mostly because we’d all be dead and have far fewer problems, period.
The importance of this work is that it demonstrates the existence of superconductors at room temperature. This new material has a temperature 50 degrees Fahrenheit warmer than any previously known superconductor, which would make it an impressive step forward even if we were still working in super-cooled temperatures below freezing. Although the amount of pressure required to reach this operational state makes implementation impossible, we now have a known method of solving this problem. Where there is one, there may be more.
This discovery does not solve the problem, but it is a fundamental and necessary part of the puzzle.
Feature image by J. Adam Fenster / University of Rochester.