Heading to the terahertz with superconductors

One day, although it is unlikely that many of us will witness it, systems with a speed of one terahertz will exist. The path that still separates us from that milestone is long and winding, so each step along the way is noteworthy.

And it is true that as speed increases, so does complexity, and in this situation, we are talking about a jump that pushes us to confront a long-standing difficulty.

The evolution to exceed the limits of silicon, the semiconductor that has been responsible for the evolution of computing and technology for decades, is an example of such complexity.

And it's because, for many years, we've been talking about carbon nanotubes, which will allow us to keep progressing in shrinking the size of the elements that make up the integrated ones.

Remember that silicon cannot be thinner than three nanometers in order to avoid electrical leaks (at least in theory). However, save for surprise, we will have to wait for the arrival of nanotubes.

This, after so many years of study, "only" allows us to jump from three to two nanometers, so imagine the technological evolution required to move from the 5, 2 gigahertz found in an Intel Core i9-12900K up to terahertz.

Remember that terahertz is equal to a thousand gigahertz, thus we're multiplying the present speed by 200.

As a result, we no longer only have a size problem, but also a material problem. Semiconductors, particularly silicon, have shown to be extremely beneficial thus far and will continue to be so in the short to medium term.

However, just as we are approaching its size constraints, we will eventually reach its maximum speed restrictions as well. In other words, because semiconductors cannot reach terahertz frequencies, superconductors will be required.

However, there are two issues with this sort of material: its lack of unidirectionality and its heat demands, both of which must be handled in order to continue progress toward terahertz.

To understand it, you should be familiar with the physics of semiconductors and superconductors, which will also help you understand why semiconductors have been and continue to be the monarchs of electronics.

The conductivity conditions of semiconductors are lower than those of superconductors, as implied by their names. However, by definition, they allow defining a unidirectional flow that permits channeling the "traffic" in the desired direction by applying a specific voltage.

Something similar has been attempted with superconductors for decades in order to make use of their higher conductivity, but it has not been possible until now.

Superconductors have extremely low critical temperatures. In reality, the current goal of this research team is to develop technology that can operate at full capacity at temperatures over 77 degrees Kelvin (-196.15 degrees Celsius), as this temperature can be sustained using liquid nitrogen.

However, the needed temperature is currently significantly lower. As a result, the terahertz is still a long way from being a reality, at least for the time being.

We may think similarly about temperature control and the issues that will emerge later in the race to terahertz.