A new type of unconventional superconductivity has been observed in graphene, promising to revolutionize energy and technology.

Superconducting materials are used today to power a wide variety of applications, from MRI machines to particle accelerators, but they have limitations, such as the need for extremely low temperatures. Now, a scientific team has taken new steps to overcome them.

The research is based on observations of a version of graphene, an extremely thin, strong, flexible and lightweight two-dimensional material of carbon atoms, properties that make it unique.

The details are published in the journal Science , in an article led by physicists from the Massachusetts Institute of Technology (MIT) in the United States. Superconductors are like express trains.

Any electricity that "goes up" to one of these materials can pass through it without stopping or losing energy along the way. That's why they are extremely energy efficient.

However, conventional ones have limited use, as they must be cooled to ultra-low temperatures using sophisticated cooling systems to maintain them in their superconducting state.

If these could operate at higher temperatures, similar to ambient temperatures, it would open doors to a new world of technologies, from electrical cables and power grids without energy loss to practical quantum computing systems, details a statement from MIT.

Therefore, scientists from various centers are studying unconventional superconductors, materials that exhibit superconductivity in different and potentially more promising ways than current ones. And this is precisely what is described this Thursday in Science, a "promising advance," according to its authors.

Specifically, the researchers report new evidence of unconventional superconductivity in a version of graphene called "magic angle" twisted trilayer graphene.

This material is manufactured by stacking three one-atom-thick sheets of graphene at a specific angle, or twist, which allows exotic properties to emerge. This material had already shown indirect signs of unconventional superconductivity and other unusual electronic behaviors in the past.

The new discovery offers the most direct confirmation yet that the material exhibits unconventional superconductivity, MIT summarizes. Graphene was isolated 18 years ago by Russians Andre Geim and Konstantin Novoselov—who received the Nobel Prize in Physics in 2010.

The incredible properties of graphene were presented in a single layer of material, but over the years the scientific community realized that the qualities could change by putting one sheet on top of another.

In 2010, a series of theoretical articles were published stating that, if in addition to placing two layers, these are rotated at a small angle, the electronic properties are significantly modified.

At MIT, led by the Spaniard Pablo Jarillo-Herrero - who also co-authored today's article - they then began working with twisted bilayer graphene, initially using rotations with large angles, which also produce attractive changes in properties, and later with small angles, which brought the surprise.

The first interesting results appeared in 2016, but it wasn't until 2018 that two behaviors of magic-angle twisted graphene—as the tiny twist angle used came to be called—were discovered that no one had predicted. The new version of graphene could become both an insulator and a superconductor, switching between the two properties. The findings gave rise to an entirely new field known as "twistronics"—twist being the English word for twist.

The new study in Science presents evidence of unconventional superconductivity in one of these graphene sheets, but this time a three-layered one. Specifically, the team was able to measure what is called the "superconducting gap," a property that describes the resistance of a material to the superconducting state at certain temperatures.

They found that the superconducting gap is very different from that of typical superconductors, which means that the mechanism by which the material becomes superconducting must also be different and unconventional.

The researchers made their discovery using a new experimental platform that essentially allows them to observe the superconducting gap as superconductivity emerges in two-dimensional materials, in real time.

"A thorough understanding of one unconventional superconductor can unlock our understanding of the rest," summarizes Jarillo-Herrero. "This understanding can guide the design of superconductors that operate at room temperature, for example, which is a kind of holy grail for the entire field."