Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quantum spin could create unstoppable, one-dimensional electron waves

19.11.2015

New theory points the way forward to transform atom-thin materials into powerful conductors

In certain nanomaterials, electrons are able to race through custom-built roadways just one atom wide. To achieve excellent efficiency, these one-dimensional paths must be paved with absolute perfection--a single errant atom can stop racing electrons in their tracks or even launch it backwards. Unfortunately, such imperfections are inevitable.

Now, a pair of scientists from the U.S. Department of Energy's Brookhaven National Laboratory and Ludwig Maximilian University in Munich have proposed the first solution to such subatomic stoppage: a novel way to create a more robust electron wave by binding together the electron's direction of movement and its spin. The trick, as described in a paper published November 16 in Physical Review Letters and featured as an Editor's Selection, is to exploit magnetic ions lacing the electron racetrack. The theory could drive advances in nanoscale engineering for data- and energy-storage technologies.

"One-dimensional materials can only be very good conductors if they are defect-free, but nothing in this world is perfect," said Brookhaven physicist Alexei Tsvelik, one of two authors on the paper. "Our theory, the first of its kind, lays out a way to protect electron waves and optimize these materials."

The work relies on a model system called a Kondo chain, where flowing electrons interact with local magnetic moments within a material. Properly harnessed, this powerful interaction could allow materials to behave like perfect conductors and offer high efficiency.

Protecting the transport

Atom-wide channels only allow motion in one of two opposing directions: right or left. Electrons traveling through such a narrow path--racing along in what are called charge-density waves--can be easily reversed by virtually any obstacle.

"The wave rises like an electronic tsunami that is expected to carry electrons smoothly in one direction," Tsvelik said. "But it turns out that this tsunami can be very easily pinned by disorder, by impurities in the material."

This "tsunami" shifts direction through a conductivity-smothering phenomenon called backscattering--like a wave breaking against sheer cliffs. But while direction is easily reversed, another feature of the electron is much more resilient: spin. The spin of an electron--like a perpetually spinning quantum top--can only be described as either up or down, and it is impervious to simple imperfections in the material. The trick, then, is to teach the directional wave to lean on spin for support.

"As the electrons flow, they interact with magnetic moments embedded in the material--these pockets of intrinsic magnetism are the key to producing the bound state," said Ludwig Maximilian University physicist Oleg Yevtushenko, the other collaborator on the paper. "The magnetic moments bind spin and direction tightly together, so any disturbance would need to flip the electron's spin in order to change its direction."

These rolling electron waves could then be described as right-moving with spin up, left-moving with spin down, and so on. In each instance, the direction is bolstered by spin.

Building an electron bicycle

Imagine walking along a narrow path barely wide enough for both feet. In such a simple system, turning around is easy--one can pivot around at the slightest provocation.

"But what if we give our pedestrian a bicycle?" Tsvelik said. "It suddenly becomes very difficult to break that angular momentum and change directions--especially on such a narrow path. This bound spin-direction state is like our electron's bicycle, keeping it rolling along powerfully enough to overcome bumps in the one-dimensional road."

To verify the efficacy of this theoretical electron bicycle, scientists will need to apply this theory to stringent tests.

"The magnetic ions in materials such as cesium, iron, and manganese all make excellent candidates for generating and exploring this promising bound state," Yevtushenko said.

The process of synthesizing functional one-dimensional materials--as thin metallic wires or paths conjured by chemistry--continues to evolve and push both theory and industry forward. Scientists in Brookhaven Lab's Condensed Matter Physics and Materials Science Department and Center for Functional Nanomaterials specialize in similar one-of-a-kind atomic architectures.

"We hope our colleagues will leap at this challenge, especially as it's the only method proposed to enhance flow at this 1D scale," Tsvelik said. "Who knows where these fundamental concepts might lead? The wonder of science is that it brings surprise."

###

This work was funded by the DOE Office of Science.

Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE's Office of Science by Brookhaven Science Associates, a limited-liability company founded by the Research Foundation for the State University of New York on behalf of Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit applied science and technology organization.

Related Links

Scientific paper: "Quantum Phase Transition and Protected Ideal Transport in a Kondo Chain" [http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.216402]

Media Contact

Karen McNulty Walsh
kmcnulty@bnl.gov
631-344-8350

 @brookhavenlab

http://www.bnl.gov 

Karen McNulty Walsh | EurekAlert!

Further reports about: Electrons Energy QUANTUM bicycle electron waves material technologies waves

More articles from Materials Sciences:

nachricht Epoxy compound gets a graphene bump
14.11.2018 | Rice University

nachricht Automated adhesive film placement and stringer integration for aircraft manufacture
15.11.2018 | Fraunhofer IFAM

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

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...

Im Focus: A Chip with Blood Vessels

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...

Im Focus: A Leap Into Quantum Technology

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...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>