A brand new fusion of materials, each with special electrical properties, has all of the components required for a novel form of superconductivity that might provide the idea for more robust quantum computing. The brand new combination of materials, created by a team led by researchers at Penn State, could also provide a platform to explore physical behaviors just like those of mysterious, theoretical particles often known as chiral Majoranas, which may very well be one other promising component for quantum computing.
The brand new study appeared online today (Feb. 8) within the journal Science. The work describes how the researchers combined the 2 magnetic materials in what they called a critical step toward realizing the emergent interfacial superconductivity, which they’re currently working toward.
Superconductors — materials with no electrical resistance — are widely utilized in digital circuits, the powerful magnets in magnetic resonance imaging (MRI) and particle accelerators, and other technology where maximizing the flow of electricity is crucial. When superconductors are combined with materials called magnetic topological insulators — thin movies only a number of atoms thick which have been made magnetic and restrict the movement of electrons to their edges — the novel electrical properties of every component work together to supply “chiral topological superconductors.” The topology, or specialized geometries and symmetries of matter, generates unique electrical phenomena within the superconductor, which could facilitate the development of topological quantum computers.
Quantum computers have the potential to perform complex calculations in a fraction of the time it takes traditional computers because, unlike traditional computers which store data as a one or a zero, the quantum bits of quantum computers store data concurrently in a spread of possible states. Topological quantum computers further improve upon quantum computing by making the most of how electrical properties are organized to make the computers robust to decoherence, or the loss of data that happens when a quantum system is just not perfectly isolated.
“Creating chiral topological superconductors is a very important step toward topological quantum computation that may very well be scaled up for broad use,” said Cui-Zu Chang, Henry W. Knerr Early Profession Professor and associate professor of physics at Penn State and co-corresponding creator of the paper. “Chiral topological superconductivity requires three ingredients: superconductivity, ferromagnetism and a property called topological order. On this study, we produced a system with all three of those properties.”
The researchers used a way called molecular beam epitaxy to stack together a topological insulator that has been made magnetic and an iron chalcogenide (FeTe), a promising transition metal for harnessing superconductivity. The topological insulator is a ferromagnet — a form of magnet whose electrons spin the identical way — while FeTe is an antiferromagnet, whose electrons spin in alternating directions. The researchers used quite a lot of imaging techniques and other methods to characterize the structure and electrical properties of the resulting combined material and confirmed the presence of all three critical components of chiral topological superconductivity on the interface between the materials.
Prior work in the sector has focused on combining superconductors and nonmagnetic topological insulators. In line with the researchers, adding within the ferromagnet has been particularly difficult.
“Normally, superconductivity and ferromagnetism compete with one another, so it’s rare to seek out robust superconductivity in a ferromagnetic material system,” said Chao-Xing Liu, professor of physics at Penn State and co-corresponding creator of the paper. “However the superconductivity in this method is definitely very robust against the ferromagnetism. You would want a really strong magnetic field to remove the superconductivity.”
The research team remains to be exploring why superconductivity and ferromagnetism coexist in this method.
“It’s actually quite interesting because we’ve got two magnetic materials which are non-superconducting, but we put them together and the interface between these two compounds produces very robust superconductivity,” Chang said. “Iron chalcogenide is antiferromagnetic, and we anticipate its antiferromagnetic property is weakened across the interface to offer rise to the emergent superconductivity, but we want more experiments and theoretical work to confirm if that is true and to make clear the superconducting mechanism.”
The researchers said they imagine this method can be useful within the seek for material systems that exhibit similar behaviors as Majorana particles — theoretical subatomic particles first hypothesized in 1937. Majorana particles act as their very own antiparticle, a novel property that might potentially allow them for use as quantum bits in quantum computers.
“Providing experimental evidence for the existence of chiral Majorana can be a critical step within the creation of a topological quantum computer,” Chang said. “Our field has had a rocky past in trying to seek out these elusive particles, but we predict this can be a promising platform for exploring Majorana physics.”
Along with Chang and Liu, the research team at Penn State on the time of the research included postdoctoral researcher Hemian Yi; graduate students Yi-Fan Zhao, Ruobing Mei, Zi-Jie Yan, Ling-Jie Zhou, Ruoxi Zhang, Zihao Wang, Stephen Paolini and Run Xiao; assistant research professors within the Materials Research Institute Ke Wang and Anthony Richardella; Evan Pugh University Professor Emeritus of Physics Moses Chan; and Verne M. Willaman Professor of Physics and Professor of Materials Science and Engineering Nitin Samarth. The research team also includes Ying-Ting Chan and Weida Wu at Rutgers University; Jiaqi Cai and Xiaodong Xu on the University of Washington; Xianxin Wu on the Chinese Academy of Sciences; John Singleton and Laurel Winter on the National High Magnetic Field Laboratory; Purnima Balakrishnan and Alexander Grutter on the National Institute of Standards and Technology; and Thomas Prokscha, Zaher Salman, and Andreas Suter on the Paul Scherrer Institute of Switzerland.
This research is supported by the U.S. Department of Energy. Additional support was provided by the U.S. National Science Foundation (NSF), the NSF-funded Materials Research Science and Engineering Center for Nanoscale Science at Penn State, the Army Research Office, the Air Force Office of Scientific Research, the state of Florida and the Gordon and Betty Moore Foundation’s EPiQS Initiative.
