An international team of researchers, headed by the researchers from the Center for Quantum Materials at the University of Minnesota, were surprised to discover that deformations in quantum materials that cause imperfections in the crystal structure have the potential to enhance the superconducting and electrical characteristics of the material.
Image Credit: University of Minnesota.
The remarkable discovery could offer new insights for developing the next generation of quantum-based computing and electronic devices. The study was published in the journal Nature Materials, a peer-reviewed scientific journal published by Nature Publishing Group.
Quantum materials have unusual magnetic and electrical properties that, if understood and controlled, could revolutionize virtually every aspect of society and enable highly energy-efficient electrical systems and faster, more accurate electronic devices. The ability to tune and modify the properties of quantum materials is pivotal to advances in both fundamental research and modern technology.
Martin Greven, Study Co-Author, Distinguished McKnight Professor and Director, Center for Quantum Materials, School of Physics and Astronomy University of Minnesota
When a material is stressed, it leads to elastic deformation but returns to its original shape after the stress is removed. On the other hand, plastic deformation is a non-reversible change in the shape of a material in response to the applied stress — in simple words, the action of squeezing and stretching until it loses its shape.
Blacksmiths and engineers have used plastic deformation for thousands of years. An example of a material with a large plastic deformation is wet chewing gum, which can be stretched multiple times than its original length.
Elastic deformation has been greatly used to understand and manipulate quantum materials. However, plastic deformation is not yet studied sufficiently. Traditional knowledge would support scientists to believe that “squeezing” or “stretching” quantum materials may remove their most intriguing characteristics.
As part of this novel study, the researchers employed plastic deformation to develop extended periodic defect structures in a prominent quantum material called strontium titanate (SrTiO3). Changes to the electrical properties and boosting of superconductivity were induced by these defect structures.
We were quite surprised with the results. We went into this thinking that our techniques would really mess up the material. We would have never guessed that these imperfections would actually improve the materials’ superconducting properties, which means that, at low enough temperatures, it could carry electricity without any energy waste.
Martin Greven, Study Co-Author, Distinguished McKnight Professor and Director, Center for Quantum Materials, School of Physics and Astronomy University of Minnesota
According to Greven, the study explains the significant promise of plastic deformation as a tool to manipulate and develop new quantum materials. It can also result in novel electronic characteristics, including materials with high potential for application in technology.
Greven also added that the new study denotes the power of state-of-the-art neutron and x-ray scattering probes in deciphering the complex structures of quantum materials and of a scientific technique that integrates both experiment and theory.
Scientists can now use these techniques and tools to study thousands of other materials. I expect that we will discover all kinds of new phenomena along the way.
Martin Greven, Study Co-Author, Distinguished McKnight Professor and Director, Center for Quantum Materials, School of Physics and Astronomy University of Minnesota
Apart from the University of Minnesota, the team included researchers from the University of Zagreb, Croatia; Ariel University, Israel; Peking University, Beijing, China; Oak Ridge National Laboratory; and Argonne National Laboratory.
The research was financially supported by the U.S. Department of Energy Office of Science. The team used resources at the Spallation Neutron Source at Oak Ridge National Laboratory and the Advanced Photon Source at Argonne National Laboratory, which are both U.S. Department of Energy Office of Science facilities. The researchers also used facilities at the Minnesota Nano Center at the University of Minnesota, which is supported by the National Science Foundation.
Journal Reference:
Hameed, S., et al. (2021) Enhanced superconductivity and ferroelectric quantum criticality in plastically deformed strontium titanate. Nature Materials. doi.org/10.1038/s41563-021-01102-3.