Featured Research

from universities, journals, and other organizations

Novel technique opens door to better solar cells, superconductors and hard drives

Date:
April 14, 2014
Source:
National University of Singapore
Summary:
A new invention solves long-standing mystery in the physics of condensed matter and enhances our understanding of interfaces between materials.

This shows Dr. Anil Annadi, Asst Prof Ariando, Asst Prof Andrivo Rusydi and Mr. Teguh Citra Asmara of the Dept of Physics at NUS Faculty of Science (from left to right) with the spectroscopic ellipsometry facility utilized in the study.
Credit: National University of Singapore

A team of scientists, led by Assistant Professor Andrivo Rusydi from the Department of Physics at the National University of Singapore's (NUS) Faculty of Science, has successfully developed a technique to study the interface between materials, shedding light on the new properties that arise when two materials are put together.

Related Articles


With a better understanding of how materials interface, scientists can tweak the properties of different materials more easily, and this opens doors to the development of better solar cells, novel superconductors and smaller hard drives.

The team's research findings were first published in scientific journal Nature Communication on 14 April 2014.

Solving mysteries in condensed matter physics

Some of the most exciting condensed matter physics problems are found at the interfaces of dissimilar materials.

"If you put two materials together, you can create completely new properties. For instance, two non-conducting, non-magnetic insulators can become conducting and in some cases ferromagnetic and superconducting at their interface," explained Asst Prof Rusydi. "The problem is that we do not fully understand what is happening at the interface yet."

To resolve this long-standing mystery in the physics of condensed matter, the NUS scientists investigated the interface between strontium titanate and lanthanum aluminate, two insulators that become conductors at their interface. In doing this, the team uncovered another mystery.

"For this interface, a theory predicts that the conductivity should be tenfold higher than what is observed. So, 90 per cent of the charge carriers -- the electrons -- are missing. It is a complete mystery to us why this happened," said Asst Prof Rusydi.

To search for the missing electrons, the scientists employed high-energy reflectivity coupled with spectroscopic ellipsometry. They utilised the bright synchrotron radiation source at the Singapore Synchrotron Light Source at NUS and Deutsches Elektronen-Synchrotron and floodlighted the interface of the two materials with a wide energy range.

The absorption of synchrotron radiation at specific wavelengths revealed the energy state of the corresponding electrons and unveiled their hiding place in the crystal lattice. It was found that only about 10 per cent of the expected electrons are free to migrate to the interface of the two materials to form a conduction band. The remaining 90 per cent are bound in the molecular lattice at higher energy states that were not visible to light sources used in earlier searches.

"This came as a surprise," said Asst Prof Rusydi. "But it also explains why more than just one layer is necessary to fully unfold the interface properties."

He further elaborated, "All the electrons in the material are like small antenna that respond to electromagnetic radiation at different wavelengths, depending on their energy state. If only a part of the electrons migrate to the interface, you need a bigger volume to compensate for the symmetry breaking."

Further research to better understand interfaces

The technique developed by the NUS scientists is the start of their investigation on the basic interface characteristics among materials. The team expects that with a better understanding of interfaces, their properties can be more easily tweaked to desired characteristics.

In the next step of their research, Asst Prof Rusydi and his team will study the interfaces between other materials. They are also working on building a new and unique floodlight facility at the Singapore Synchrotron Light Source in NUS to be used in their research to reveal quantum properties at the interfaces of complex systems.


Story Source:

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


Journal Reference:

  1. T.C. Asmara, A. Annadi, I. Santoso, P.K. Gogoi, A. Kotlov, H.M. Omer, M. Motapothula, M.B.H. Breese, M. Rόbhausen, T. Venkatesan, Ariando, A. Rusydi. Mechanisms of charge transfer and redistribution in LaAlO3/SrTiO3 revealed by high-energy optical conductivity. Nature Communications, 2014; 5 DOI: 10.1038/ncomms4663

Cite This Page:

National University of Singapore. "Novel technique opens door to better solar cells, superconductors and hard drives." ScienceDaily. ScienceDaily, 14 April 2014. <www.sciencedaily.com/releases/2014/04/140414091958.htm>.
National University of Singapore. (2014, April 14). Novel technique opens door to better solar cells, superconductors and hard drives. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2014/04/140414091958.htm
National University of Singapore. "Novel technique opens door to better solar cells, superconductors and hard drives." ScienceDaily. www.sciencedaily.com/releases/2014/04/140414091958.htm (accessed October 25, 2014).

Share This



More Matter & Energy News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) — IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) — A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
Real-Life Transformer Robot Walks, Then Folds Into a Car

Real-Life Transformer Robot Walks, Then Folds Into a Car

Buzz60 (Oct. 24, 2014) — Brave Robotics and Asratec teamed with original Transformers toy company Tomy to create a functional 5-foot-tall humanoid robot that can march and fold itself into a 3-foot-long sports car. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Police Testing New Gunfire Tracking Technology

Police Testing New Gunfire Tracking Technology

AP (Oct. 24, 2014) — A California-based startup has designed new law enforcement technology that aims to automatically alert dispatch when an officer's gun is unholstered and fired. Two law enforcement agencies are currently testing the technology. (Oct. 24) Video provided by AP
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:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

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