Navigation Links
A 'nanoscale landscape' controls flow of surface electrons on a topological insulator
Date:10/25/2012

CHESTNUT HILL, MA (October 25, 2012) In the relatively new scientific frontier of topological insulators, theoretical and experimental physicists have been studying the surfaces of these unique materials for insights into the behavior of electrons that display some very un-electron-like properties.

In topological insulators, electrons can behave more like photons, or particles of light. The hitch is that unlike photons, electrons have a mass that normally plays a defining role in their behavior. In the world of quantum physics, where everyday materials take on surprising and sometimes astonishing properties, electrons on the outer surface of these insulators behave and look uncharacteristically like light.

These unique properties have piqued the interests of scientists who see future applications in areas such as quantum computing and spintronics, or other realms rooted in the manipulation of electronic properties. The early challenge to those researchers is to begin to understand some simple ground rules for controlling these materials.

Boston College researchers report that the placement of tiny ripples on the surface of a topological insulator engineered from bismuth telluride effectively modulates so-called Dirac electrons so they flow in a pathway that perfectly mirrors the topography of the crystal's surface.

Associate Professor of Physics Vidya Madhavan and Assistant Professor of Physics Stephen Wilson report in the current online edition of Nature Communications that scanning tunneling microscopy is capable of revealing the characteristics of these tiny waves as they rise and fall, enabling the researchers to draw a direct connection between the features of the ripples and modulation of the waves across the material's surface.

Instead of chaotic behavior, the electrons flow in a path that mirrors the metal composite's surface, the team reports in an articled titled "Ripple-modulated electronic structure of a 3D topological insulator."

"What we've discovered is that electrons respond beautifully to this buckling of the material's surface," said Madhavan, the project director.

So harmoniously do the waves flow across the ripples placed approximately 100 nanometers apart that the researchers say further modifications of the crystal's "nanoscale landscape" could produce enough control to produce a one-dimensional quantum wire capable of carrying current with no dissipation.

The rippled surface appears to exert greater control and run less risk of creating imperfections than other methods, such as introducing chemical dopants, used in attempts to modulate the flow of electrons on the surface of other topological insulators, the researchers found.

Madhavan said the team had to provoke the electrons, which lay placidly atop the surface-state of the insulator, much like the glassy surface of an undisturbed lake. The team disrupted the electrons by introducing impurities, which had an effect similar to that of dropping a stone in a calm lake. This provocation produced waves of electrons that behave like waves of light as they travel pathways that mirror the contours created in the crystal.

"We did not expect the electrons to follow the topography," said Madhavan. "The topography imposes a sinusoidal potential upon the waves. The ripples create that potential by giving the electrons a landscape to follow. This is a way of possibly manipulating these electrons in topological insulators."


'/>"/>

Contact: Ed Hayward
ed.hayward@bc.edu
617-552-4826
Boston College
Source:Eurekalert

Related biology technology :

1. Penn and Brown researchers demonstrate earthquake friction effect at the nanoscale
2. Carving at the nanoscale
3. ORNL experiments prove nanoscale metallic conductivity in ferroelectrics
4. Magnetic actuation enables nanoscale thermal analysis
5. Solved: The mystery of the nanoscale crop circles
6. Nanoscale magnetic media diagnostics by rippling spin waves
7. UCLA-led research team develops worlds most powerful nanoscale microwave oscillators
8. First 3-D nanoscale optical cavities from metamaterials
9. Ferroelectricity on the nanoscale
10. New UCLA Engineering research center to revolutionize nanoscale electromagnetic devices
11. Manufacturing complex 3-D metallic structures at nanoscale made possible
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/27/2017)... -- The new research portal will give visitors ... on Valero Energy , offering extensive market research on ... ... http://photos.prnewswire.com/prnh/20160330/349511LOGO) The latest trend gaining momentum ... today, even though touted as a green alternative to fossil ...
(Date:3/27/2017)... , March 27, 2017 DarioHealth Corp. (NASDAQ: ... health and big data solutions, today announced that it ... coverage option for U.S. consumers who want to have ... DarioHealth has signed strategic alliance agreements with partners across ... coverage benefits, and if approved, will supply and bill ...
(Date:3/24/2017)... -- Research and Markets has announced the addition of ... Business Report" report to their offering. ... This report analyzes the Global market ... estimates and forecasts are provided for the period 2014 through 2022. ... The report profiles 25 companies including many key ...
(Date:3/24/2017)... Agenus Inc. (NASDAQ: AGEN), an immuno-oncology company ... vaccines, today announced participation at the following conferences: ... and Maidstone Life Sciences conference "Cancer Immunotherapy Conference" at ... New York, NY . Agenus will participate in ... am: Robert B. Stein , M.D., Ph.D., President, ...
Breaking Biology Technology:
(Date:3/23/2017)... PUNE, India , March 23, 2017 The report ... Equipment, Touchless Biometric), Industry, and Geography - Global Forecast to 2022", published by ... growing at a CAGR of 29.63% between 2017 and 2022. ... ... Logo ...
(Date:3/20/2017)... At this year,s CeBIT Chancellor Dr. Angela ... The Chancellor came to the DERMALOG stand together with the Japanese Prime ... partner country. At the largest German biometrics company the two government leaders ... iris recognition as well as DERMALOGĀ“s multi-biometrics system.   ... ...
(Date:3/9/2017)... and MOUNTAIN VIEW, Calif. , March ... Made Simple," and 23andMe , the leading personal ... food choices.  Zipongo can now provide customers with personalized ... health goals and biometrics, but also genetic markers impacting ... Zipongo,s personalized food decision support platform uses ...
Breaking Biology News(10 mins):