Featured Research

from universities, journals, and other organizations

New control over topological insulator

Date:
March 20, 2014
Source:
University of York
Summary:
Scientists investigating the electronic properties of ultra-thin films of new materials -- topological insulators (TIs) -- have demonstrated a new method to tune their unique properties using strain. Topological insulators are new materials with surfaces that host a new quantum state of matter and are insensitive to contaminants, defects and impurities. Surface electrons in TIs behave like massless Dirac particles in a similar way to electrons in graphene. Moreover, surface currents in topological insulators also preserve their spin orientation and coherence on a macro scale.

An international team of scientists investigating the electronic properties of ultra-thin films of new materials -- topological insulators (TIs) -- has demonstrated a new method to tune their unique properties using strain.
Credit: Image courtesy of University of York

An international team of scientists investigating the electronic properties of ultra-thin films of new materials -- topological insulators (TIs) -- has demonstrated a new method to tune their unique properties using strain.Topological insulators are new materials with surfaces that host a new quantum state of matter and are insensitive to contaminants, defects and impurities. Surface electrons in TIs behave like massless Dirac particles in a similar way to electrons in graphene. Moreover, surface currents in topological insulators also preserve their spin orientation and coherence on a macro scale.

The research, carried out by physicists from the University of York, UK, the University of Wisconsin, Milwaukee, USA, and the University of Cadiz, Spain is reported in the journal Nature Physics. The ability to control the surface electronic states of TIs is a crucial step in the realisation of their potential in highly energy efficient spintronic devices.

Dr Vlado Lazarov, from York's Department of Physics, said: "These inherent properties of TIs, and the interplay between magnetism and proximity to superconductors, make topological insulators a prime platform for the realisation of solid state quantum computing devices. "The ability to control the surface electronic state of the TIs is a crucial step in realising their potential in energy efficient devices. Through our research, we have shown that it is possible to tune the properties using strain.

"Using Scanning Tunneling Microscopy at UW-Milwaukee and aberration corrected Transmission Electron Microscopy at the York-JEOL Nanocentre, the researchers demonstrated that tensile strain can lift the topological order, while compressive strain can shift in energy the characteristic Dirac point.

Professor Lian Li, from UW-Milwaukee, said: "Using these advanced microscopes, we examined the low-angle tilt grain boundaries in Bi2Se3(0001) films and found that they consist of arrays of alternating edge dislocation pairs.

Along the boundary, these dislocations introduce different types of strain -- compressive and tensile. "Through further tunnelling spectroscopy measurements and quantum mechanical calculations, we discovered that Dirac states are enhanced under tensile strain and destroyed under compressive strain. These findings suggest new ways to control TIs' electronic properties, for example, by applying stress."

The York physicists carried out atomistic studies at the York-JEOL Nanocentre at the University of York, a world-class research and teaching facility. The research was supported by the National Science Foundation, USA (DMR-1105839) and a Royal Society international exchange grant.


Story Source:

The above story is based on materials provided by University of York. Note: Materials may be edited for content and length.


Journal Reference:

  1. Y. Liu, Y. Y. Li, S. Rajput, D. Gilks, L. Lari, P. L. Galindo, M. Weinert, V. K. Lazarov, L. Li. Tuning Dirac states by strain in the topological insulator Bi2Se3. Nature Physics, 2014; DOI: 10.1038/NPHYS2898

Cite This Page:

University of York. "New control over topological insulator." ScienceDaily. ScienceDaily, 20 March 2014. <www.sciencedaily.com/releases/2014/03/140320101136.htm>.
University of York. (2014, March 20). New control over topological insulator. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2014/03/140320101136.htm
University of York. "New control over topological insulator." ScienceDaily. www.sciencedaily.com/releases/2014/03/140320101136.htm (accessed July 23, 2014).

Share This




More Matter & Energy News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com
Boeing Ups Outlook on 52% Profit Jump

Boeing Ups Outlook on 52% Profit Jump

Reuters - Business Video Online (July 23, 2014) Commercial aircraft deliveries rose seven percent at Boeing, prompting the aerospace company to boost full-year profit guidance- though quarterly revenues missed analyst estimates. Bobbi Rebell reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Car Market on the Rebound?

Europe's Car Market on the Rebound?

Reuters - Business Video Online (July 23, 2014) Daimler kicks off a round of second-quarter earnings results from Europe's top carmakers with a healthy set of numbers - prompting hopes that stronger sales in Europe will counter weakness in emerging markets. Hayley Platt reports. Video provided by Reuters
Powered by NewsLook.com
9/11 Commission Members Warn of Terror "fatigue" Among American Public

9/11 Commission Members Warn of Terror "fatigue" Among American Public

Reuters - US Online Video (July 22, 2014) Ten years after releasing its initial report, members of the 9/11 Commission warn of the "waning sense of urgency" in combating terrorists attacks. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins