Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Scientists open door to better solar cells, superconductors and hard-drives: Research enhances understanding of materials interfaces

Left: If the lanthanum aluminate layer (blue) is less than three unit cells, the electrons redistribute in sub-layers. Right: If the layer has four unit cells or more, some electrons migrate to the interface. Credit: Michael Rübhausen, University of Hamburg
Left: If the lanthanum aluminate layer (blue) is less than three unit cells, the electrons redistribute in sub-layers. Right: If the layer has four unit cells or more, some electrons migrate to the interface.

Credit: Michael Rübhausen, University of Hamburg

Abstract:
Using DESY's bright research light sources, scientists have opened a new door to better solar cells, novel superconductors and smaller hard-drives. The research reported in the scientific journal Nature Communications this week enhances the understanding of the interface of two materials, where completely new properties can arise. With their work, the team of Prof. Andrivo Rusydi from the National University of Singapore and Prof. Michael Rübhausen from the Hamburg Center for Free-Electron Laser Science (CFEL) have solved a long standing mystery in the physics of condensed matter. CFEL is a cooperation of DESY, the University of Hamburg and the Max Planck Society.

Scientists open door to better solar cells, superconductors and hard-drives: Research enhances understanding of materials interfaces

Hamburg, Germany | Posted on April 14th, 2014

"Interfaces are a hot topic in materials research," says Rusydi. "If two dissimilar materials are put together, completely new properties may be generated. For instance, two insulators and non-magnetic materials can become metallic and magnetic at their interface." The reason for this change of personality of the two materials is the broken symmetry at the interface, explains Rübhausen, who is a professor at the University of Hamburg. "The two materials have different characteristics and different structures. If you put them together, they have to make a deal and rearrange, and this leads to new properties."

Making use of these phenomena can lead to smaller hard-drives, for example. "Conventional hard-drives are currently controlled by bulk physical properties of the material, for miniaturization we would like to control their physical properties by the interface structure," says Rusydi. "The problem is that we do not yet fully understand what is happening at the interface." As an example, the team investigated the interface of strontium titanate (SrTiO3) and lanthanum aluminate (LaAlO3), two insulators that become conductors at their interface. "However, based on Maxwell's theory, a tenfold higher conductivity should be observed. So, 90 per cent of the charge carriers, the electrons, have gone missing. That was a complete mystery to us," says Rusydi.

In search of the "missing electrons" the scientists used DESY's bright synchrotron radiation source DORIS III to floodlight the interface of the two materials in a wider ultraviolet energy range than any investigation had used before. "All the electrons in the material are like small antenna that respond to electromagnetic radiation at different wavelengths, depending on their energy state," explains Rusydi. The absorption of synchrotron radiation at specific wavelengths reveals the energy state of the corresponding electrons and thus their hiding place in the crystal lattice.

The investigation showed that only a fraction of the expected electrons actually migrate to the interface to form a conducting layer. Most of the electrons redistribute in sub-layers within the lanthanum aluminate, where they were hidden from techniques used in previous investigations. Also, the scientists observed that the transfer of electrons from the crystal to the interface depends on the number of so-called unit cells of lanthanum aluminate in the crystal lattice. A unit cell is the smallest unit of a crystal, this means a crystal can be described as many identical unit cells. If the lanthanum aluminate layer is less than three unit cells thick, all electrons redistribute within the lanthanum aluminate sub-layers and no electrons transfer to the interface anymore which then remains an insulator.

This explains, why more than just one layer is necessary to fully unfold the interface properties. "If only a part of the electrons migrate to the interface, you need a bigger volume to compensate for the symmetry breaking," explains Rusydi. With their work, the scientists can now better understand the behaviour of this and of other interfaces. "In principle, our experimental technique can be used to study any interface," says Rübhausen. "We have only just begun to investigate the basic interface characteristics with it." Although further investigations will have to wait until the Superlumi experimental station that has been used for this work has been moved from the now retired light source DORIS III to DESY's current machine PETRA III. "There currently is no facility in the world that can measure this," Rübhausen says.

The scientists expect that with a better understanding of interfaces, their properties can be more easily tweaked to desired characteristics. "If we learn to control the interface, we can design completely new properties and control them," says Rübhausen.

####

About Deutsches Elektronen-Synchrotron DESY
Deutsches Elektronen-Synchrotron DESY is the leading German accelerator centre and one of the leading in the world. DESY is a member of the Helmholtz Association and receives its funding from the German Federal Ministry of Education and Research (BMBF) (90 percent) and the German federal states of Hamburg and Brandenburg (10 percent). At its locations in Hamburg and Zeuthen near Berlin, DESY develops, builds and operates large particle accelerators, and uses them to investigate the structure of matter. DESY's combination of photon science and particle physics is unique in Europe.

For more information, please click here

Contacts:
Dr. Thomas Zoufal

49-408-998-1666

Copyright © Deutsches Elektronen-Synchrotron DESY

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 Links

Reference

Related News Press

News and information

Multi-million pound project to use nanotechnology to improve safety September 4th, 2015

Magnetic wormhole connecting 2 regions of space created for the first time: The device could have applications in medicine, opening up ways to make MRIs more comfortable for patients September 4th, 2015

Tongfang Global and QD Vision Partner to Bring Wide Color Gamut to Global Television Lines: Color IQTM quantum dots help boost company’s focus on superior color reproduction September 3rd, 2015

QEOS and GLOBALFOUNDRIES to Offer Industry’s First CMOS Platform for MillimeterWave Markets: GLOBALSOLUTIONSSM Partnership will enable next-generation wireless technologies for applications in IoT, 5G and automotive September 3rd, 2015

Chip Technology

GLOBALFOUNDRIES and Catena Partner to Provide Next-Generation RF Connectivity Solutions for Growing Wireless Markets: Catena Wi-Fi and Bluetooth RF technologies available on GLOBALFOUNDRIES 28nm Super Low Power Process technology September 3rd, 2015

For 2-D boron, it's all about that base: Rice University theorists show flat boron form would depend on metal substrates September 2nd, 2015

Phagraphene, a 'relative' of graphene, discovered September 2nd, 2015

Nanometrics to Participate in the Citi 2015 Global Technology Conference August 26th, 2015

Memory Technology

New material science research may advance tech tools August 31st, 2015

'Magic' sphere for information transfer: Professor at the Lomonosov Moscow State University made the «magic» sphere for information transfer August 24th, 2015

Superlattice design realizes elusive multiferroic properties: New design sandwiches a polar metallic oxide between an insulating material August 23rd, 2015

High-precision control of nanoparticles for digital applications August 19th, 2015

Announcements

Multi-million pound project to use nanotechnology to improve safety September 4th, 2015

Magnetic wormhole connecting 2 regions of space created for the first time: The device could have applications in medicine, opening up ways to make MRIs more comfortable for patients September 4th, 2015

Making nanowires from protein and DNA September 3rd, 2015

Making fuel from light: Argonne research sheds light on photosynthesis and creation of solar fuel September 3rd, 2015

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Magnetic wormhole connecting 2 regions of space created for the first time: The device could have applications in medicine, opening up ways to make MRIs more comfortable for patients September 4th, 2015

Making nanowires from protein and DNA September 3rd, 2015

Making fuel from light: Argonne research sheds light on photosynthesis and creation of solar fuel September 3rd, 2015

Reversible Writing with Light: Self-assembling nanoparticles take their cues from their surroundings September 3rd, 2015

Energy

Making fuel from light: Argonne research sheds light on photosynthesis and creation of solar fuel September 3rd, 2015

For 2-D boron, it's all about that base: Rice University theorists show flat boron form would depend on metal substrates September 2nd, 2015

Phagraphene, a 'relative' of graphene, discovered September 2nd, 2015

RUSNANOPRIZE Directorate Announces New Deadline for Nominations Submission – September 11, 2015 September 1st, 2015

Solar/Photovoltaic

Making fuel from light: Argonne research sheds light on photosynthesis and creation of solar fuel September 3rd, 2015

Phagraphene, a 'relative' of graphene, discovered September 2nd, 2015

Hot electrons point the way to perfect light absorption: Physicists study how to achieve perfect absorption of light with the help of rough ultrathin films September 1st, 2015

Artificial leaf harnesses sunlight for efficient fuel production August 30th, 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







Car Brands
Buy website traffic