Science for SciFi: Superconductors

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A room-temperature super conductor would revolutionize the energy industry and how we build electrical devices. But what is a superconductor? Why do we care whether it works at room temperature or not?

In short, a superconductor is a material that can conduct electricity without resistance.

Resistance is an important, and useful quality of many materials. Some things are just less conductive than others. Obviously for wires we want a low resistance, but for other components a higher resistance may be required. It’s the context and the application that mattes.

And there are some really cool applications for superconductors. But the equipment required to keep them at temperatures cold enough to maintain their superconductivity limits their use. But they have such potential!

Let’s get one thing out of the way first. When someone says “low-temperature superconductor” they mean superconductors that become superconductors at liquid helium temperatures. A “high-temperature superconductor” works at liquid nitrogen temperatures. The temperature at which a conductor becomes a superconductor is called its critical temperature.

So how do they work?

Gui et al. described superconductivity as “…a competing balance between stable geometric structures and unstable electronic structures.”1

A greatly simplified explanation of how superconductors work is that they enable the formation of Cooper pairs. Cooper pairs are pairs of electrons with opposite spins and momentum. These electrons are so strongly pairs that they move through a superconductor without resistance as their interactions with the atoms they encounter are too weak to break them apart.

Researchers seek to create new superconductors by searching for new combinations and arrangements of atoms that result in improved superconductors.

The geometry of a molecule plays a massive role in it’s properties, and this extends to . This is because bonds between atoms are made by paired electrons, and pairs so electrons repel other pairs of electrons. Electronegativity, bond angle and length can thus influence the energy level of electrons around the nucleus and in the crystal structures that the atoms and molecule are a part of.

If we ever find a naturally occurring superconductor on another planet it will probably be an alloy or crystal structure caused by local conditions. We might for example find a rare allotrope of a previously discovered metal. So rather than mining it like in James Cameron’s movie about blue people, we would probably find a way to make it ourselves before too long.

Superconductors are already used to make the magnets in MRI/NMR machines where stronger magnets provide higher levels of resolution. They are also used to build the transistors used in experimental computers, and to build some maglev trains and superconducting power lines. However, as long as specialized cooling systems are required for these applications, we will not be able to reap the full benefits that superconductivity offers.

Once achieved, room-temperature super conductors would change everything, and could enable many of the technologies in your setting’s space ships. Perhaps the star drive is built around a superconducting warp coil, and in order to conserve reaction mass the ship is wired with superconducting cables, and superconducting antennas are used to pick up weak signals sent from distant stars.

  1. “Chemistry in Superconductors” 2021. Chemical Reviews. American chemical Society.

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