Researchers at Penn State University have succeeded in fusing materials with special electrical properties into a new material that displays characteristics of the mysterious theoretical particles known as Chiral Majoranas. The properties of this new fusion material could be used to build more robust quantum computers in the future.
First hypothesized in 1937, Majorana particles are theoretical subatomic particles that can also act as their antiparticle. The concept has remained a theory for nearly a century but now assumes importance as quantum computing rises.
Unlike conventional computers that store their data in either 0 or 1, quantum computers can store them simultaneously in a range of possible states called quantum bits or qubits. While this increases the scale of computations that can be performed, it also increases the chances of errors accompanying the computation. Researchers believe that Majorana particles could serve as qubits with their own antiparticle, making quantum computing more robust.
Unique superconductor for quantum computing
Superconductors are materials that do not offer any internal resistance. They are used in digital circuits and to make powerful magnets in equipment like MRI machines and particle accelerators. When combined with magnetic topological insulators - material that is just a few atoms thick but with properties to restrict the movement of electrons, the two materials combine to form chiral topological superconductors.
The topology or special geometry and symmetry of this new material gives some unique properties to the superconductor, which can then be used to build topological quantum computers that are more robust than classical quantum computers. This is because the electrical properties of the superconductor prevent the loss of information from the quantum system.
"Creating chiral topological superconductors is an important step toward topological quantum computation that could be scaled up for broad use," said Cui-Zu Chang, an associated professor of physics at Penn State who was involved in the research.
How was the fusion material created?
Chiral topological superconductivity involves three properties: superconductivity, ferromagnetism, and topological order. To imbibe the fusion material with all three properties, the researchers turned to a method known as molecular beam epitaxy.
This approach allowed the team to stack Iron Telluride (FeTe), an iron-based superconductor, with a topological insulator. The insulator was a ferromagnet where the electrons spin the same way. At the same time, FeTe is an anti-ferromagnet in which electrons spin in alternating directions.
Using various imaging techniques and other methods, the team confirmed that the fusion material had all the three properties required to call it a chiral topological superconductor. Previous research in the field has demonstrated the fusion of superconductors and nonmagnetic insulators, whereas in this case, the team has managed to team up the superconductor with a magnetic insulator.
"Superconductivity and ferromagnetism compete with each other, so it is rare to find robust superconductivity in a ferromagnetic material system," added Chao-Xing Liu, professor of physics at Penn State, in a press release. "Superconductivity in this system is actually very robust against the ferromagnetism. You would need a very strong magnetic field to remove the superconductivity." The researchers have yet to figure out how superconductivity and ferromagnetism coexist in their material.
Recently, the field of material science went through a tumultuous period of exaggerated claims without sufficient scientific examination. Aware of this, Chang added, "Our field has had a rocky past in trying to find these elusive particles, but we think this is a promising platform for exploring Majorana physics."
The research findings were published today in .
