(Press-News.org) UNIVERSITY PARK, Pa. — A new fusion of materials, each with special electrical properties, has all the components required for a unique type of superconductivity that could provide the basis for more robust quantum computing. The new combination of materials, created by a team led by researchers at Penn State, could also provide a platform to explore physical behaviors similar to those of mysterious, theoretical particles known as chiral Majoranas, which could be another promising component for quantum computing.
The new study appeared online today (Feb. 8) in the journal Science. The work describes how the researchers combined the two magnetic materials in what they called a critical step toward realizing the emergent interfacial superconductivity, which they are currently working toward.
Superconductors — materials with no electrical resistance — are widely used 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 films only a few atoms thick that have been made magnetic and restrict the movement of electrons to their edges — the novel electrical properties of each component work together to produce “chiral topological superconductors.” The topology, or specialized geometries and symmetries of matter, generates unique electrical phenomena in the superconductor, which could facilitate the construction 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 simultaneously in a range of possible states. Topological quantum computers further improve upon quantum computing by taking advantage of how electrical properties are organized to make the computers robust to decoherence, or the loss of information that happens when a quantum system is not perfectly isolated.
“Creating chiral topological superconductors is an important step toward topological quantum computation that could be scaled up for broad use,” said Cui-Zu Chang, Henry W. Knerr Early Career Professor and associate professor of physics at Penn State and co-corresponding author of the paper. “Chiral topological superconductivity requires three ingredients: superconductivity, ferromagnetism and a property called topological order. In this study, we produced a system with all three of these properties.”
The researchers used a technique 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 type of magnet whose electrons spin the same way — while FeTe is an antiferromagnet, whose electrons spin in alternating directions. The researchers used a variety 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 at the interface between the materials.
Prior work in the field has focused on combining superconductors and nonmagnetic topological insulators. According to the researchers, adding in the ferromagnet has been particularly challenging.
“Normally, superconductivity and ferromagnetism compete with each other, so it is rare to find robust superconductivity in a ferromagnetic material system,” said Chao-Xing Liu, professor of physics at Penn State and co-corresponding author of the paper. “But the superconductivity in this system is actually very robust against the ferromagnetism. You would need a very strong magnetic field to remove the superconductivity.”
The research team is still exploring why superconductivity and ferromagnetism coexist in this system.
“It’s actually quite interesting because we have two magnetic materials that 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 around the interface to give rise to the emergent superconductivity, but we need more experiments and theoretical work to verify if this is true and to clarify the superconducting mechanism.”
The researchers said they believe this system will be useful in the search for material systems that exhibit similar behaviors as Majorana particles — theoretical subatomic particles first hypothesized in 1937. Majorana particles act as their own antiparticle, a unique property that could potentially allow them to be used as quantum bits in quantum computers.
“Providing experimental evidence for the existence of chiral Majorana will be a critical step in the creation of a topological quantum computer,” Chang said. “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.”
In addition to Chang and Liu, the research team at Penn State at 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 in 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 at the University of Washington; Xianxin Wu at the Chinese Academy of Sciences; John Singleton and Laurel Winter at the National High Magnetic Field Laboratory; Purnima Balakrishnan and Alexander Grutter at the National Institute of Standards and Technology; and Thomas Prokscha, Zaher Salman, and Andreas Suter at 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.
Combining materials may support unique superconductivity for quantum computing
ELSE PRESS RELEASES FROM THIS DATE:
The analysis of biological networks allows understanding the complexity of multiple sclerosis
International research led by the Department of Medicine and Life Sciences (MELIS) at Pompeu Fabra University, in collaboration with Hospital del Mar, Hospital Clínic, Charité - Medical University of Berlin, and the universities of Oslo and Genoa, has developed a computational biology tool, based on multi-level network analysis, to achieve an integrated vision of multiple sclerosis. This tool could be used to study other complex diseases such as types of dementia. Multiple sclerosis is an autoimmune ...
Care for life-threatening child diarrhea limited by health providers’ views
Young children in India who suffer from life-threatening diarrhea frequently are given ineffective treatments because health providers misperceive the wishes of a child’s caregiver, according to a novel new study. Using actors posing as child caregivers to examine the behavior of health providers in two divergent regions in India, researchers found that the perceived preferences of a child’s caregiver was a more important factor in the way a child was treated than the views of the health care provider about the best course of action. The ...
ANU scientists debunk role of ‘junk cells’ in fight against malaria
Researchers from The Australian National University (ANU) have discovered a previously unknown ability of a group of immune system cells, known as Atypical B cells (ABCs), to fight infectious diseases such as malaria. The discovery provides new insight into how the immune system fights infections and brings scientists a step closer to harnessing the body’s natural defences to combat malaria. The scientists say ABCs could also be key to developing new treatments for chronic autoimmune conditions such as lupus. According to the researchers, ABCs have long been associated with malaria, ...
Fibroblasts in the penis are more important for erectile function than previously thought
Regular erections could be important for maintaining erectile function, according to a new study on mice published in Science by researchers at Karolinska Institutet. “We discovered that an increased frequency of erections leads to more fibroblasts that enable erection and vice versa, that a decreased frequency results in fewer of these cells,” says principal investigator Christian Göritz. In a new study on mice, researchers at Karolinska Institutet and Uppsala University in Sweden ...
MIT physicists capture the first sounds of heat “sloshing” in a superfluid
In most materials, heat prefers to scatter. If left alone, a hotspot will gradually fade as it warms its surroundings. But in rare states of matter, heat can behave as a wave, moving back and forth somewhat like a sound wave that bounces from one end of a room to the other. In fact, this wave-like heat is what physicists call “second sound.” Signs of second sound have been observed in only a handful of materials. Now MIT physicists have captured direct images of second sound for the first time. The new images reveal how heat can move like a wave, ...
How emotions affect word retrieval in people with aphasia
COLUMBUS, Ohio – People with aphasia have more trouble coming up with words they want to use when they’re prompted by images and words that carry negative emotional meaning, new research suggests. The study involved individuals whose language limitations resulted from damage to the brain caused by a stroke – the most common cause of aphasia, affecting at least one-third of stroke survivors. The disorder impairs the expression and understanding of language as well as reading and writing. Researchers from The Ohio State University who led the study said the findings – suggesting that prompts ...
Pregnant women living in states with limited access to abortion face higher levels of intimate partner homicide
Key Takeaways Young women under the age of 30, Black women, and women with lower education levels are disproportionately affected by intimate partner homicide during pregnancy, reflecting the need to better serve and protect these vulnerable populations. Particularly by firearms, increasing rates of intimate partner homicide of women who are pregnant or recently pregnant are occurring in states that have limited access to abortion. Researchers describe a ‘dire ...
Researchers uncover genetic factors for severe Lassa fever
While combing through the human genome in 2007, computational geneticist Pardis Sabeti made a discovery that would transform her research career. As a then postdoctoral fellow at the Broad Institute of MIT and Harvard, Sabeti discovered potential evidence that some unknown mutation in a gene called LARGE1 had a beneficial effect in the Nigerian population. Other scientists had discovered that this gene was critical for the Lassa virus to enter cells. Sabeti wondered whether a mutation in LARGE1 ...
Leader in robotics at U-M and beyond elected to National Academy of Engineering
Feb. 8, 2024 Contact: Katherine McAlpine, 734-647-7087, email@example.com Image Leader in robotics at U-M and beyond elected to National Academy of Engineering Dawn Tilbury is recognized for advances in manufacturing network control and human-robot interaction, as well as engineering leadership ANN ARBOR—Dawn Tilbury, the Ronald D. and Regina C. McNeil Department Chair of Robotics at the University of Michigan, has been recognized with one of engineering's greatest honors—election to the National Academy of Engineering. NAE members are outstanding researchers, ...
16 UTA scholars receive McNair federal research award
A competitive U.S. Department of Education program that prepares undergraduate students interested in careers in academic research has selected 16 undergraduate students from The University of Texas at Arlington to join. The McNair Scholars Program was named for physicist and astronaut Ronald E. McNair, the second Black astronaut in U.S. history and one of several crew members killed when the space shuttle Challenger exploded on Jan. 28, 1986. The program assists qualified first-generation ...