The finding may pave the way to create atomic-scale superconducting elements
A research group at the NIMS International Center for Materials Nanoarchitectonics and a research team at the Institute for Solid State Physics of the University of Tokyo discovered that in an atomic-scale-thick superconductor formed on a silicon surface, a single-atom difference in height between atomic layers (atomic step) acts as a Josephson junction that controls the flow of supercurrent. The results of this research have been published in the Physical Review Letters, DOI: http://dx.doi.org/10.1103/PhysRevLett.113.247004.
Figure 2 of the press release. A 3-D diagram of an atomic-layered superconductor observed under the scanning tunneling microscope. The heights of atomic layers are depicted, and the densities of localized electron states are represented by different brightnesses. Superconducting quantum vortices exist in the bright areas near atomic steps. The differences among A, B and C are attributed to the change in strength of the respective Josephson junctions, and to the differences in the gap width between the indium atomic layers near atomic steps. In particular, C is identified as a Josephson vortex. Arrows schematically indicate the flow of supercurrent and the pattern where, as a Josephson junction weakens, the vortex elongates in the direction parallel to the atomic step.
Copyright : NIMS
（Shunsuke Yoshizawa, Howon Kim, Takuto Kawakami, Yuki Nagai, Tomonobu Nakayama, Xiao Hu, Yukio Hasegawa, and Takashi Uchihashi, Article title: “Imaging Josephson Vortices on the Surface Superconductor Si(111)−(√7×√3)−In using a Scanning Tunneling Microscope” Phys. Rev. Lett. 113, 247004 – Published 10 December 2014.）
A research group at the NIMS (Sukekatsu Ushioda, president) International Center for Materials Nanoarchitectonics (MANA, Masakazu Aono, director), consisting of post-doctoral researcher Shunsuke Yoshizawa, MANA researcher Takashi Uchihashi, MANA principal investigator Tomonobu Nakayama, post-doctoral researcher Takuto Kawakami and MANA principal investigator Xiao Hu, and a research team at the Institute for Solid State Physics of the University of Tokyo, consisting of post-doctoral researcher Kim Howon and associate professor Yukio Hasegawa, discovered that in an atomic-scale thick superconductor formed on a silicon surface, a single-atom difference in height between atomic layers (atomic step) acts as a Josephson junction that controls the flow of supercurrent.
Recently discovered atomic-layered superconductors on a silicon surface have the potential of developing into ultra-tiny, superconducting nano-devices with atomic-scale thickness. However, fabrication of such devices requires the creation of a Josephson junction, an essential component in superconducting logic elements, and the method of creating such junctions had not been well understood.
Conducting an experiment using a scanning tunneling microscope, and performing microscopic theoretical calculations, the research team recently discovered that a special superconducting state called a Josephson vortex, a type of superconducting quantum vortex, is generated at atomic steps in atomic-layered superconductors. Based on this finding, the team revealed that atomic steps act as Josephson junctions. These results also indicate that the use of atomic-layered superconductors enables quick and mass fabrication of Josephson junctions in a self-organizing manner in contrast to the current method of fabricating the junctions one by one using conventional superconducting elements.
In consideration of these findings, in the future studies, the researchers are planning to fabricate Josephson elements that are only an atomic-level thick and apply them to superconducting devices. Also, it is known that Josephson vortices play a vital role in high-temperature superconductors that are a promising technology for electric power applications. The results from this study are expected to contribute to the identification of superconducting properties of high-temperature superconductors.
This study was jointly conducted with Yuki Nagai, a researcher at the Japan Atomic Energy Agency, as a part of the world premier international research center initiative and the grants-in-aid for scientific research program sponsored by the Ministry of Education, Culture, Sports, Science and Technology.
This study has been published in Physical Review Letters, an journal of the American Physical Society, as an Editors’ Suggestion article. DOI: http://dx.doi.org/10.1103/PhysRevLett.113.247004
NIMS press release
Mikiko Tanifuji | ResearchSEA
Epoxy compound gets a graphene bump
14.11.2018 | Rice University
Automated adhesive film placement and stringer integration for aircraft manufacture
15.11.2018 | Fraunhofer IFAM
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences