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 Superconductivity research reveals potential new state of matter
17.08.2017 | DOE/Los Alamos National Laboratory

nachricht Spray-on electric rainbows: Making safer electrochromic inks
17.08.2017 | Georgia Institute of Technology

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Gold shines through properties of nano biosensors

17.08.2017 | Physics and Astronomy

Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter

17.08.2017 | Earth Sciences

Mars 2020 mission to use smart methods to seek signs of past life

17.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>