Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bending the rules

30.06.2014

A UCSB postdoctoral scholar in physics discovers a counterintuitive phenomenon: the coexistence of superconductivity with dissipation

For his doctoral dissertation in the Goldman Superconductivity Research Group at the University of Minnesota, Yu Chen, now a postdoctoral researcher at UC Santa Barbara, developed a novel way to fabricate superconducting nanocircuitry. However, the extremely small zinc nanowires he designed did some unexpected — and sort of funky — things.

Chen, along with his thesis adviser, Allen M. Goldman, and theoretical physicist Alex Kamenev, both of the University of Minnesota, spent years seeking an explanation for these extremely puzzling effects. Their findings appear this week in Nature Physics.

"We were determined to figure out how we could reconcile the strange phenomena with the longstanding rules governing superconductivity," said lead author Chen. "The coexistence of superconductivity with dissipation, which we observed, is counterintuitive and bends the rules as we know them."

Typically superconductivity and dissipation are thought to be mutually exclusive because dissipation, a process in thermodynamic systems whereby electric energy is transformed into heat, is a feature of a normal — versus a superconductive — state.

"But we discovered that superconductivity and dissipation can coexist under rather generic conditions in what appears to be a universal manner," Chen said.

After long and careful work, which involved both experimental and theoretical efforts, the researchers found an explanation that fits. Behind all of the observed phenomena is a peculiar nonequilibrium state of quasiparticles — electron-like excitations that formed in the nanowires Chen designed.

The quasiparticles are created by phase slips. In a superconductive state, when supercurrent flows through the nanowire, the quantum mechanical function describing the superconductivity of the wire evolves along the length of the wire as a spiral shaped like a child's Slinky toy. From time to time, one of the revolutions of the spiral contracts and disappears altogether. This event is called a phase slip. This quirk generates quasiparticles, giving rise to a previously undiscovered voltage plateau state where dissipation and superconductivity coexist.

"The most significant achievement was making the nanowires smaller and cooler than anyone had done previously," Kamenev said. "This allowed the quasiparticles to travel through the wire faster and avoid relaxation. This leads to a peculiar nonthermal state, which combines properties of a superconductor and a normal metal at the same time."

In addition to discovering this unique phenomenon, the team also found another heretofore-unseen property in the voltage plateau. When a magnetic field is turned on in the voltage plateau state, rather than shrinking the superconducting region, which is what would usually occur, the superconducting area expands and is enhanced.

"This is an unexpected property of very small nanowires," said Goldman.

This state appears to be universal for ultra-small superconducting circuitry like Chen's, which features ideal contacts between the nano-elements and the leads. Such nanoscale superconductors may be key components in future superconducting computer systems.

"Our findings demonstrate that superconducting nanocircuits can be used as a simple, but rather generic platform to investigate nonequilibrium quantum phenomena," Chen concluded.

"Now we need to explore the parameters of nanowires that give rise to the effect and those that don't," Goldman said. "We also need to examine the behavior of wires of different lengths and different materials in order to further define the parameters."

Julie Cohen | Eurek Alert!

Further reports about: explanation generic nanowires nonequilibrium parameters phenomena rise superconductivity voltage

More articles from Physics and Astronomy:

nachricht Hubble observes one-of-a-kind star nicknamed 'Nasty'
22.05.2015 | NASA/Goddard Space Flight Center

nachricht Basel Physicists Develop Efficient Method of Signal Transmission from Nanocomponents
22.05.2015 | Universität Basel

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Basel Physicists Develop Efficient Method of Signal Transmission from Nanocomponents

Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.

Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...

Im Focus: IoT-based Advanced Automobile Parking Navigation System

Development and implementation of an advanced automobile parking navigation platform for parking services

To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...

Im Focus: First electrical car ferry in the world in operation in Norway now

  • Siemens delivers electric propulsion system and charging stations with lithium-ion batteries charged from hydro power
  • Ferry only uses 150 kilowatt hours (kWh) per route and reduces cost of fuel by 60 percent
  • Milestone on the road to operating emission-free ferries

The world's first electrical car and passenger ferry powered by batteries has entered service in Norway. The ferry only uses 150 kWh per route, which...

Im Focus: Into the ice – RV Polarstern opens the arctic season by setting course for Spitsbergen

On Tuesday, 19 May 2015 the research icebreaker Polarstern will leave its home port in Bremerhaven, setting a course for the Arctic. Led by Dr Ilka Peeken from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) a team of 53 researchers from 11 countries will investigate the effects of climate change in the Arctic, from the surface ice floes down to the seafloor.

RV Polarstern will enter the sea-ice zone north of Spitsbergen. Covering two shallow regions on their way to deeper waters, the scientists on board will focus...

Im Focus: Gel filled with nanosponges cleans up MRSA infections

Nanoengineers at the University of California, San Diego developed a gel filled with toxin-absorbing nanosponges that could lead to an effective treatment for skin and wound infections caused by MRSA (methicillin-resistant Staphylococcus aureus), an antibiotic-resistant bacteria. This "nanosponge-hydrogel" minimized the growth of skin lesions on mice infected with MRSA - without the use of antibiotics. The researchers recently published their findings online in Advanced Materials.

To make the nanosponge-hydrogel, the team mixed nanosponges, which are nanoparticles that absorb dangerous toxins produced by MRSA, E. coli and other...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International symposium: trends in spatial analysis and modelling for a more sustainable land use

20.05.2015 | Event News

15th conference of the International Association of Colloid and Interface Scientists

18.05.2015 | Event News

EHFG 2015: Securing health in Europe. Balancing priorities, sharing responsibilities

12.05.2015 | Event News

 
Latest News

Mesoporous Particles for the Development of Drug Delivery System Safe to Human Bodies

22.05.2015 | Materials Sciences

Computing at the Speed of Light

22.05.2015 | Information Technology

Development of Gold Nanoparticles That Control Osteogenic Differentiation of Stem Cells

22.05.2015 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>