In late July, a couple of startling papers appeared on the arXiv, a repository of pre-peer-review manuscripts on topics in physics and astronomy. The papers claim to describe the synthesis of a material that is not only able to superconduct above room temperature, but also above the boiling point of water. And it does so at normal atmospheric pressures.
Instead of having to build upon years of work with exotic materials that only work under extreme conditions, the papers seem to describe a material that could be made via some relatively straightforward chemistry and would work if you set it on your desk. It was like finding a shortcut to a material that would revolutionize society.
The perfect time to write an article on those results would be when they’ve been confirmed by multiple labs. But these are not perfect times. Instead, rumors seem to be flying daily about possible confirmation, confusing and contradictory results, and informed discussions of why this material either should or shouldn’t work.
In this article, we’ll explain where things stand and why getting to a place of clarity will be challenging, even if these claims are right.
Superconductors work because there is one state shared by a bunch of electrons separated by an energy gap from other states they could be in. To put thermal energy into an atom (ie. Resistance), you have to have a big enough shift in energy for all of the electrons to shift out of the state. Kind of like they unionized and you can’t give one a pay cut on its own. One way to achieve this is to make a regular material very, very, very cold. Lots of conductors will work, but only at or below liquid helium temperatures. Another way is to find a material where there are only a few ways for electrons to move around and cool it down or squeeze it until there’s only one. The latter works at hundreds to thousands of times higher temperature (tens of kelvin rather than millikelvin), but still really cold.
Conductors have a lot of states electrons can be in. It’s very easy to get one moving, but as they play pachinko through the atomic lattice they echange tiny amounts if energy with each other and the rest of the material. Probably not a good candidate unless you’re really good at squeezing.
In some ways a high temperature superconductor is more like an insulator or a semiconductor than a regular conductor.
This new material is kinda weird in a few ways. For one, the main mechanism of traditional superconductors making all electrons “the same” so they have that grouping up effect is probably not present according to some very preliminary simulations (cooper pairs). Another is that the effect is limited to movement in one direction.
There’s 40 years of history and politics behind the theory, 30 years of experiments behind the leak from the korean project, and the material is very finnicky.