Navigation Links
Physicists isolate bound states in graphene-superconductor junctions
Date:2/14/2011

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

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.


'/>"/>

Contact: Liz Ahlberg
eahlberg@illinois.edu
217-244-1073
University of Illinois at Urbana-Champaign
Source:Eurekalert

Related biology technology :

1. McGill physicists find a new state of matter in a transistor
2. U of T physicists squeeze light to quantum limit
3. Physicists discover important step for making light crystals
4. Nanophysicists find unexpected magnetic effect
5. NYU physicists find way to explore microscopic systems through holographic video
6. Physicists at UC Santa Barbara make discovery in quantum mechanics
7. U-M physicists create first atomic-scale map of quantum dots
8. Physicists capture first images of atomic spin
9. UBC, Max Planck formalize partnership among worlds top quantum physicists
10. UC Riverside physicists pave the way for graphene-based spin computer
11. Rice physicists discover ultrasensitive microwave detector
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/23/2016)... ... June 23, 2016 , ... UAS LifeSciences, one of ... their brand, UP4™ Probiotics, into Target stores nationwide. The company, which has been ... Target to its list of well-respected retailers. This list includes such fine stores ...
(Date:6/23/2016)... , June 23, 2016 A person commits a ... crime scene to track the criminal down. An ... Food and Drug Administration (FDA) uses DNA evidence to track ... Sound far-fetched? It,s not. The FDA has increasingly ... support investigations of foodborne illnesses. Put as simply as possible, ...
(Date:6/23/2016)... June 23, 2016  The Prostate Cancer Foundation (PCF) is pleased ... and faster cures for prostate cancer. Members of the Class of 2016 were ... Read More About the Class of 2016 PCF Young ... ... ...
(Date:6/23/2016)... ... 23, 2016 , ... Supplyframe, the Industry Network for electronics ... Lab . Located in Pasadena, Calif., the Design Lab’s mission is to bring ... designed, built and brought to market. , The Design Lab is Supplyframe’s physical ...
Breaking Biology Technology:
(Date:6/9/2016)... control systems is proud to announce the introduction of fingerprint attendance control software, allowing ... are actually signing in, and to even control the opening of doors. ... ... ... Photo - http://photos.prnewswire.com/prnh/20160609/377487 ...
(Date:6/3/2016)... , June 3, 2016 ... Management) von Nepal ... und Lieferung hochsicherer geprägter Kennzeichen, einschließlich Personalisierung, ... führend in der Produktion und Implementierung von ... der Ausschreibung im Januar teilgenommen, aber Decatur ...
(Date:6/2/2016)... , June 2, 2016 Perimeter ... Platforms, Unmanned Systems, Physical Infrastructure, Support & Other Service  ... visiongain offers comprehensive analysis of the global ... market will generate revenues of $17.98 billion in 2016. ... DVTEL Inc, a leader in software and hardware technologies ...
Breaking Biology News(10 mins):