Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > A 'nanoscale landscape' controls flow of surface electrons on a topological insulator: Stripe-like contours on a surface modulate electrons that behave like light

Abstract:
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.

A 'nanoscale landscape' controls flow of surface electrons on a topological insulator: Stripe-like contours on a surface modulate electrons that behave like light

Chestnut Hill, MA | Posted on October 25th, 2012

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."

In addition to Madhavan and Wilson, the project team included post-doctoral researcher Yoshinori Okada and graduate students Wenwen Zhou, Daniel Walkup and Chetan Dhital.

NOTE: The report "Ripple-modulated electronic structure of a 3D topological insulator" can be cited via a digital object identifier (DOI) number. The DOI for this article is 10.1038/ncomms2150.

####

For more information, please click here

Contacts:
Ed Hayward

617-552-4826

Copyright © Boston College

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Miniature Technology, Large-Scale Impact: Winner of the 2015 Lindros Award for translational medicine, Kjeld Janssen is pushing the boundaries of the emerging lab-on-a-chip technology - See more at: http://www.news.ucsb.edu/2015/015744/miniature-technology-large-scale-impact#stha July 7th, 2015

Tel Aviv/Tsinghua University project uses crowd computing to improve water filtration: The research, a product of the new TAU-Tsinghua XIN Center, was conducted by 150,000 volunteers at IBM's World Community Grid July 6th, 2015

Transition from 3 to 2 dimensions increases conduction, MIPT scientists discover July 6th, 2015

A Stretchy Mesh Heater for Sore Muscles July 6th, 2015

Spintronics

Fundamental observation of spin-controlled electrical conduction in metals: Ultrafast terahertz spectroscopy yields direct insight into the building block of modern magnetic memories July 6th, 2015

Influential Interfaces Lead to Advances in Organic Spintronics July 1st, 2015

Emergence of a 'devil's staircase' in a spin-valve system July 1st, 2015

Spintronics advance brings wafer-scale quantum devices closer to reality June 24th, 2015

Chip Technology

Fundamental observation of spin-controlled electrical conduction in metals: Ultrafast terahertz spectroscopy yields direct insight into the building block of modern magnetic memories July 6th, 2015

Transition from 3 to 2 dimensions increases conduction, MIPT scientists discover July 6th, 2015

Nanometrics to Announce Second Quarter Financial Results on July 23, 2015 July 2nd, 2015

The quantum middle man July 2nd, 2015

Quantum Computing

The quantum middle man July 2nd, 2015

Freezing single atoms to absolute zero with microwaves brings quantum technology closer: Atoms frozen to absolute zero using microwaves July 2nd, 2015

Producing spin-entangled electrons July 2nd, 2015

Opening a new route to photonics Berkeley lab researchers find way to control light in densely packed nanowaveguides June 27th, 2015

Discoveries

Miniature Technology, Large-Scale Impact: Winner of the 2015 Lindros Award for translational medicine, Kjeld Janssen is pushing the boundaries of the emerging lab-on-a-chip technology - See more at: http://www.news.ucsb.edu/2015/015744/miniature-technology-large-scale-impact#stha July 7th, 2015

Fundamental observation of spin-controlled electrical conduction in metals: Ultrafast terahertz spectroscopy yields direct insight into the building block of modern magnetic memories July 6th, 2015

Surfing a wake of light: Researchers observe and control light wakes for the first time July 6th, 2015

Transition from 3 to 2 dimensions increases conduction, MIPT scientists discover July 6th, 2015

Announcements

Miniature Technology, Large-Scale Impact: Winner of the 2015 Lindros Award for translational medicine, Kjeld Janssen is pushing the boundaries of the emerging lab-on-a-chip technology - See more at: http://www.news.ucsb.edu/2015/015744/miniature-technology-large-scale-impact#stha July 7th, 2015

Tel Aviv/Tsinghua University project uses crowd computing to improve water filtration: The research, a product of the new TAU-Tsinghua XIN Center, was conducted by 150,000 volunteers at IBM's World Community Grid July 6th, 2015

Transition from 3 to 2 dimensions increases conduction, MIPT scientists discover July 6th, 2015

A Stretchy Mesh Heater for Sore Muscles July 6th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project