Nanocryotron Device Acts Like Superconductivity Switch, Facilitates Operation of New Particle Colliders

Advancements in physics have led scientists to build particle colliders that can reveal the hidden secrets of the universe's tiniest particles. In using these tools, minute particles leave extremely faint electrical traces after being generated in enormous collisions.

(Photo: Wikimedia Commons/ Z22)

Some detectors in these facilities rely on superconductivity, a phenomenon in which electricity is carried with zero resistance at low temperatures to function. To observe the behavior of these particles more accurately, the weak signals or currents are multiplied by a tool capable of turning a faint electrical signal into a real jolt.

Giving Particle Detectors a Boost

A group of researchers at the U.S. Department of Energy's Argonne National Laboratory has developed a novel device that can act as a 'current multiplier.' Known as a nanocryotron, this device is the natural evolution of the original macroscopic cryotron superconducting switch. The results of their study are discussed in the paper "Design and performance of parallel-channel nanocryotrons in magnetic fields.."

According to study author Tomas Polakovic, the process is like taking a small signal and using it to trigger an electric cascade. As the tiny current of these detectors is funneled into the switching device, it can also be used to switch a much bigger current.

Preparing the nanocryotron for a collider experiment takes some more work due to the involvement of high magnetic fields. Conventional particle detectors can withstand magnetic fields as strong as several tesla, but the new device's performance degrades in high magnetic fields.

When incorporating the device into a natural experiment, it is important to find ways to make it function in a higher magnetic field. To make this possible, the research team plans to change the geometry of the material and introduce defects or tiny holes. The defects can help the researchers stabilize small superconducting vortices in the materials. Such movement can lead to an unexpected disruption of superconductivity.

Polakovic and his colleagues created the nanocryotron using electron beam lithography. This stenciling technique uses a beam of electrons to remove a polymer film to expose a specific region of interest. This material is then engraved using plasma ion etching.

The researchers strip away the exposed parts, leaving behind the device they want to use. The novel device can serve as the basis for electronic logic circuitry.

This work is vital for collider experiments, like those conducted at the Electron-Ion Collider at Brookhaven National Laboratory. In this facility, the superconducting nanowire detectors positioned close to the beams would need microelectronics immune to magnetic fields.

What are Nanocryotrons?

Over the past few years, cryogenic electronics technologies have emerged as a potential solution to interface quantum systems. Experts require an intermediate step in this approach, such as superconducting cryogenic electronics known as nanocryotrons. These materials are designed to build simple superconducting circuits that allow the integration of complementary metal-oxide-semiconductor (CMOS).

A nanocryotron is a prototype for a mechanism that can raise a particle's electrical signal high enough to temporarily turn off the material's superconductivity. This makes it able to function like an on-off switch.