19 September 2012

Observing electrons in topological insulators could lead to new electronic devices

Researchers at MIT have developed techniques to observe the unusual behaviour of electrons in topological insulators (TIs) – recently discovered exotic materials that could promise new kinds of electronic devices.

The team created three dimensional 'movies' that capture increments of time down to the level of femtoseconds and catch the motions of electrons as they scatter in response to a short pulse of light.

With TIs, the bulk of the material acts as an insulator, but the surface is even more conductive than normal metals, allowing electrons to travel at almost the speed of light and be unaffected by impurities in the material. TIs could therefore enable new electronic circuits and data storage devices.

The technique developed by the researchers uses a short pulse of laser light to energise the material, causing electrons to scatter, and a second, slightly delayed pulse to illuminate it and produce an image. The process is then repeated, with the second laser pulse delayed by ever increasing increments of just a few femtoseconds. Each resulting image shows the response of the electrons to the beam after a corresponding interval. These images can then be assembled into a movie that shows how the response changes with time.

By using this technique, the researchers say they have already discovered interactions between a TI's surface and bulk electrons that had never been seen before, revealing new details of how TIs work.

"With this 3d movie, in real time we can visualise how one population of electrons [those on the surface] scatters into the other population [inside the material]," said assistant professor of physics Nuh Gedik. "This is very important to understand."

The researchers found that the interaction between the two is mediated by sound waves, and that this interaction happens much more intensely at high temperatures. According to the team, understanding this interaction will guide future work and applications of these materials.

Simon Fogg

Supporting Information


This material is protected by Findlay Media copyright
See Terms and Conditions.
One-off usage is permitted but bulk copying is not.
For multiple copies contact the sales team.

Do you have any comments about this article?

Add your comments


Your comments/feedback may be edited prior to publishing. Not all entries will be published.
Please view our Terms and Conditions before leaving a comment.

Related Articles

Amp works at 50% efficiency

Researchers from the Universities of Bristol and Cardiff have created an ...

Materials breakthrough

A technique to study the interface between materials, developed at the National ...

Quantum logic gate created

Professor Gerhard Rempe, director of the Max Planck Institute of Quantum ...

Down to the wire

Once the plain old telephone service, the role of the telephone wire continues ...

Within touching distance

Graphene is starting to filter onto the market. HEAD claims its tennis racquets ...

Making light work of photonics

Today's world is permeated by electronics, from industry to communications, ...

NI Trend Watch 2014

This report from National Instruments summarises the latest trends in the ...

Capactive sensing

This whitepaper looks at a number of capacitive sensing applications to ...

Altium's Innovation Station

An introduction to the Altium Innovation Station. It includes an overview of ...

IBM tackles 22nm challenges

IBM has announced the semiconductor industry’s first computationally based ...

BEEAs 2013

9th October 2014, 8 Northumberland, London

Self-destructing electronics

Researchers at Iowa State University have created transient electronics that ...

MEMS switch for 'true 4G'

General Electric has created a 3GHz RF MEMS switch that can handle up to 5kW of ...

Smart fabrics developed at NPL

NPL has developed a new method to produce conductive textiles. The technique ...

Electronic charge to 800mph

Breaking the land speed record would require a very special blend of latest ...

Flash drives semi technologies

Demand for NAND flash is said to be growing at 45% per year, driven mainly by ...

Top tech trends for 2013

Bee Thakore, European technical marketing manager for element14, gives an ...

Nathan Hill, director, NGI

Research into graphene won Andre Geim and Kostya Novoselov the Nobel prize in ...

Brent Hudson, Sagentia

Sagentia's ceo tells Graham Pitcher how the consulting company is anticipating ...

Prof Donal Bradley, Imperial

Graham Pitcher talks to a researcher who was 'there at the start' of the ...