Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Physicists Isolate Bound States in Graphene Superconductor Junctions

Scanning electron micrograph of a device with an overlaid measurement circuit. Graphene is false coloured orange, large end contacts are Cr/Au and middle tunnel probes are Pb/In. The scale bar is 5 ým. Credit Nature
Scanning electron micrograph of a device with an overlaid measurement circuit. Graphene is false coloured orange, large end contacts are Cr/Au and middle tunnel probes are Pb/In. The scale bar is 5 ým. Credit Nature

Abstract:
Illinois researchers have documented the first observations of some unusual physics when two prominent electric materials are connected: superconductors and graphene.

Physicists Isolate Bound States in Graphene Superconductor Junctions

Champaign, IL | Posted on February 15th, 2011

Led by University of Illinois physics professor Nadya Mason, the group published its findings in the journal Nature Physics.

When a current is applied to a normal conductor, such as metal or graphene, it flows through the material as a stream of single electrons. By contrast, electrons travel in pairs in superconductors. Yet when a normal material is sandwiched between superconductors, the normal metal can carry the supercurrent.

Normal metals can adopt superconducting capacity because the paired electrons from the superconductor are translated to special electron-hole pairs in the normal metal, called Andreev bound states (ABS).

"If you have two superconductors with a normal metal between, you can actually transport the superconductivity across the normal material via these bound states, even though the normal material doesn't have the electron pairing that the superconductors do," Mason said.

ABS are extremely difficult to measure or to observe directly. Researchers can measure conduction and overall magnitude of a current, but have not been able to study individual ABS to understand the fundamental physics contributing to these unique states.

Mason's group developed a method of isolating individual ABS by connecting superconducting probes to tiny, nanoscale flakes of graphene called quantum dots. This confined the ABS to discrete energy levels within the quantum dot, allowing the researchers to measure the superconducting ABS individually and even to manipulate them.

"Before this, it wasn't really possible to understand the fundamentals of what is transporting the current," Mason said. "Watching an individual bound state allows you to change one parameter and see how one mode changes. You can really get at a systematic understanding. It also allows you to manipulate ABS to use them for different things that just couldn't be done before."

Superconductor junctions have been proposed for use as superconducting transistors or bits for quantum computers, called qubits. Greater understanding of ABS may enable other applications as well. In addition, it may be possible to use the superconducting graphene quantum dots themselves as solid-state qubits.

"This is a unique case where we found something that we couldn't have discovered without using all of these different elements - without the graphene, or the superconductor, or the quantum dot, it wouldn't have worked. All of these are really necessary to see this unusual state," Mason said.

The U.S. Department of Energy supported this work, conducted at the Frederick Seitz Materials Research Laboratory at Illinois.

The paper, "Transport Through Andreev Bound States in a Graphene Quantum Dot," is online at www.nature.com/nphys/journal/vaop/ncurrent/full/nphys1911.html.

####

For more information, please click here

Contacts:
Liz Ahlberg
Physical Sciences Editor
217-244-1073

Copyright © University of Illinois at Urbana-Champaign

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Physics

Cooling massive objects to the quantum ground state April 1st, 2015

Quantum teleportation on a chip: A significant step towards ultra-high speed quantum computers April 1st, 2015

News and information

Quantum teleportation on a chip: A significant step towards ultra-high speed quantum computers April 1st, 2015

So, near and yet so far: Stable HGNs for Raman April 1st, 2015

Two-dimensional dirac materials: Structure, properties, and rarity April 1st, 2015

Govt.-Legislation/Regulation/Funding/Policy

Cooling massive objects to the quantum ground state April 1st, 2015

Two-dimensional dirac materials: Structure, properties, and rarity April 1st, 2015

Rutgers, NIST physicists report technology with potential for sub-micron optical switches March 31st, 2015

SUNY Poly CNSE and Title Sponsor SEFCU Name Capital Region Teams Advancing to the Final Round of the 2015 New York Business Plan Competition March 30th, 2015

Possible Futures

Nanotechnology in Medical Devices Market is expected to reach $8.5 Billion by 2019 March 25th, 2015

Nanotechnology Enabled Drug Delivery to Influence Future Diagnosis and Treatments of Diseases March 21st, 2015

Nanocomposites Market Growth, Industry Outlook To 2020 by Grand View Research, Inc. March 21st, 2015

Nanotechnology Drug Delivery Market in the US 2012-2016 : Latest Report Available by Radiant Insights, Inc March 16th, 2015

Academic/Education

SUNY Poly CNSE and Title Sponsor SEFCU Name Capital Region Teams Advancing to the Final Round of the 2015 New York Business Plan Competition March 30th, 2015

LAMDAMAP 2015 hosted by the University March 26th, 2015

SUNY Poly & M+W Make Major Announcement: Major Expansion To Include M+W Owned Gehrlicher Solar America Corporation That Will Create up to 400 Jobs to Develop Solar Power Plants at SUNY Poly Sites Across New York State March 26th, 2015

SUNY POLY CNSE to Host First Ever Northeast Semi Supply Conference (NESCO) Conference Will Connect New and Emerging Innovators in the Northeastern US and Canada with Industry Leaders and Strategic Investors to Discuss Future Growth Opportunities in NYS March 25th, 2015

Nanotubes/Buckyballs

From tobacco to cyberwood March 31st, 2015

Wrapping carbon nanotubes in polymers enhances their performance: Scientists at Japan's Kyushu University say polymer-wrapped carbon nanotubes hold much promise in biotechnology and energy applications March 30th, 2015

Carbon nanotube fibers make superior links to brain: Rice University invention provides two-way communication with neurons March 25th, 2015

Iranian Scientists Eliminate Expensive Materials from Diabetes Diagnosis Sensors March 25th, 2015

Quantum Computing

Quantum teleportation on a chip: A significant step towards ultra-high speed quantum computers April 1st, 2015

Next important step toward quantum computer: Scientists at the University of Bonn have succeeded in linking 2 different quantum systems March 30th, 2015

A first glimpse inside a macroscopic quantum state March 28th, 2015

Quantum compute this -- WSU mathematicians build code to take on toughest of cyber attacks: Revamped knapsack code offers online security for the future March 26th, 2015

Discoveries

A novel way to apply drugs to dental plaque Nanoparticles release drugs to reduce tooth decay April 1st, 2015

Quantum teleportation on a chip: A significant step towards ultra-high speed quantum computers April 1st, 2015

Two-dimensional dirac materials: Structure, properties, and rarity April 1st, 2015

3-D neural structure guided with biocompatible nanofiber scaffolds and hydrogels April 1st, 2015

Announcements

Quantum teleportation on a chip: A significant step towards ultra-high speed quantum computers April 1st, 2015

So, near and yet so far: Stable HGNs for Raman April 1st, 2015

Two-dimensional dirac materials: Structure, properties, and rarity April 1st, 2015

3-D neural structure guided with biocompatible nanofiber scaffolds and hydrogels April 1st, 2015

Quantum Dots/Rods

Next important step toward quantum computer: Scientists at the University of Bonn have succeeded in linking 2 different quantum systems March 30th, 2015

Tiny bio-robot is a germ suited-up with graphene quantum dots March 24th, 2015

Rice fine-tunes quantum dots from coal: Rice University scientists gain control of electronic, fluorescent properties of coal-based graphene March 18th, 2015

Ghent University leads large-scale European training project on quantum dots March 13th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE