One day, though it is not clear that many of us will see it, there will be systems with a speed of one terahertz. The road that still separates us from this milestone is long and winding, so every step of the way is something that needs to be emphasized. And it is the case that the complexity increases with increasing speed, and in this case we are talking about a leap that is forcing us to face a challenge that has been in place for a long time.

An example of such complexity we find ourselves in the evolution of overcoming the limits of silicon, a semiconductor that has been responsible for the development of computer technology for decades. And this is because we have been talking for many years, for example, about carbon nanotubes, which will allow us to continue to reduce the size of the elements that make up the integrated ones. Recall that to avoid electrical leaks, silicon cannot fall below three nanometers (at least in theory). However, we will have to wait for the arrival of nanotubes, to our surprise.

With so many years of research, “only” (I quote this because it’s a really big success) to be able to jump from three to two nanometers, so imagine the technological development that is necessary for you to be able to move. from the 5.2 gigahertz we currently find in the Intel Core i9-12900K to terahertz. Recall that a terahertz is a thousand gigahertz, so we’re talking about it multiply the current speed by 200.

so here we are no longer just a problem of size, but also of materials. Semiconductors, and silicon in particular, have proven to be extremely successful so far and will continue to do so in the short to medium term. However, just as we are approaching its size limits, sooner or later we will do so in terms of its maximum speed. In other words, terahertz cannot be achieved with semiconductors, the use of superconductors will be necessary.

However, this type of material has two problems: its lack of unidirectionality and its demands in the thermal part, two complex issues that need to be addressed in order to continue moving towards the terahertz. To understand this, there are some semiconductor and superconductor physics concepts that you should know about that will also help you understand why semiconductors were and are the kings of electronics.

As their names suggest, the conductivity conditions of semiconductors are lower than those of superconductors. However, by its nature allow you to define a direct current when using a certain voltage which allows you to direct “traffic” in the desired direction. For decades, superconductors have tried something similar to use their better conductivity, but so far this has not been possible.

I say this only now because a recent study by researchers at Delft University of Technology has been able to take a huge step by specific material that would allow direct regulation of the electrical passage through the superconductor. It is the researchers themselves who sign this success, who directly associate it with the ability to form integrated with the speeds that can reach terahertz.

However, there is another major problem: temperature. And no, unlike current chips, I’m not talking about its scattering, because one of the advantages of superconductors over semiconductors is that when used at critical temperatures, they become perfect conductors, that is, the resistance becomes zero, so that the current can flow indefinitely without decreasing, without any loss. The problem, of course, is that critical temperature.

Critical superconductor temperatures are low, very low. In fact, the current goal of this research team is ensure that your technology can operate at full power at temperatures above 77 degrees Kelvin (-196.15 degrees Celsius) because this temperature could be maintained with liquid nitrogen. At this point, however, the required temperature is much lower. So, at least for now, terahertz is far from becoming a reality.

However, even though I repeat that we will still have to wait, the truth is that this research would solve a problem that lasted for many decadesand this was considered practically impossible at the time. The same can be thought of about thermal control and the challenges that will arise later in the terahertz race.