Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Discovery of Josephson Junctions Generated in Atomic-Layered Superconductors

05.02.2015

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


Associated links
NIMS press release

Mikiko Tanifuji | ResearchSEA
Further information:
http://www.researchsea.com

More articles from Materials Sciences:

nachricht Physics, photosynthesis and solar cells
01.12.2016 | University of California - Riverside

nachricht New process produces hydrogen at much lower temperature
01.12.2016 | Waseda University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers uncover protein-based “cancer signature”

05.12.2016 | Life Sciences

The Nagoya Protocol Creates Disadvantages for Many Countries when Applied to Microorganisms

05.12.2016 | Life Sciences

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>