Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Interfaces provide new control over oxides' electronic properties

Provided/Kyle Shen
An artist's rendering of a transition metal oxide superlattice, with an actual transmission electron microscopy image superimposed on the left panel. The red is manganese, yellow is lanthanum and blue is strontium. The top is a Fermi surface map which illustrates how electrons move in the material.
Provided/Kyle Shen

An artist's rendering of a transition metal oxide superlattice, with an actual transmission electron microscopy image superimposed on the left panel. The red is manganese, yellow is lanthanum and blue is strontium. The top is a Fermi surface map which illustrates how electrons move in the material.

Abstract:
Materials called transition metal oxides have physicists intrigued by their potentially useful properties -- from magnetoresistance (the reason a hard drive can write memory) to superconductivity.

Interfaces provide new control over oxides' electronic properties

Ithaca, NY | Posted on September 4th, 2012

By combining two sophisticated experimental tools -- oxide molecular beam expitaxy and angle-resolved photoemission spectroscopy -- researchers have gained the first insights into quantum interactions in transition metal oxide superlattices, which are artificial stacked layers of alternating materials, each just a few atoms thick.

Even slight modifications to the stacking sequence can switch the entire superlattice from a conductive to insulating state, due to the enhancement of quantum interactions between the electrons. The findings were published online Aug. 19 in the journal Nature Materials.

"We are interested in superlattices of transition metal oxides because they can exhibit all sorts of exotic electronic and magnetic properties that do not exist in the bulk of these materials," said Kyle Shen, assistant professor of physics and paper's senior author. "They might be useful someday, but from a scientific standpoint, they are just really fascinating because the electrons can conspire to give rise to very unexpected emergent phenomena."

For some transition metal oxide superlattices, it has been shown that adding just one extra layer of atoms to the stacked layers switches them from conductor to insulator. Shen and his colleagues wanted to understand why this occurs.

To do this, the team tapped the expertise of co-author Darrell Schlom, the Herbert Fisk Johnson Professor of Industrial Chemistry in the Department of Materials Science and Engineering, who with postdoctoral scholar Carolina Adamo, created specifically designed stacks of two oxides, lanthanum manganese oxide and strontium manganese oxide, each just a few atomic layers thick and with atomic precision. To make the superlattices, they used molecular beam epitaxy, which is like spray-painting with the elements of the periodic table.

The team then utilized a unique piece of instrumentation designed and built by Shen and Schlom's groups at Cornell. It allowed them to study the superlattices after synthesis by angle-resolved photoemission spectroscopy without exposing the surfaces to air, which would contaminate the sample and obscure the sensitive experiments. Eric Monkman, a graduate student in Shen's group, and colleagues then measured and analyzed how the electrons move through different kinds of superlattices.

It turned out that the distances between the interfaces of the lanthanum and strontium oxides were the key: Pushing the interfaces farther apart made the electrons more confined to each individual interface, resulting in an enhancement of the quantum interactions, which drive the entire superlattice into an insulating state.

By pushing the interfaces closer together, the electrons could start to move between interfaces, resulting in a metallic state. The researchers were able to reach these conclusions through the use of photoemission spectroscopy, which maps the motion of electrons in solids at the atomic scale.

Advanced transmission electron microscopy imaging led by David A. Muller, Cornell professor of applied and engineering physics and co-director of the Kavli Institute at Cornell for Nanoscale Science, and graduate student Julia Mundy, confirmed that the interfaces between the lanthanum and strontium were indeed sharp, which helped confirm the quantum interactions.

The paper's co-first authors are Monkman and Adamo. Shen, Schlom and Muller are members of the Kavli Institute at Cornell for Nanoscale Science. The research was supported by the National Science Foundation through the Cornell Center for Materials Research and a Career award.

####

For more information, please click here

Contacts:
Media Contact:
Syl Kacapyr
(607) 255-7701


Cornell Chronicle:
Anne Ju
(607) 255-9735

Copyright © Cornell University

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

In IEDM 2016 Keynote, Leti CEO Says ‘Hyperconnectivity’, Human-focused Research and the IOT Promise Profound, Positive Changes December 7th, 2016

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Physics

Shape matters when light meets atom: Mapping the interaction of a single atom with a single photon may inform design of quantum devices December 4th, 2016

Deep insights from surface reactions: Researchers use Stampede supercomputer to study new chemical sensing methods, desalination and bacterial energy production December 2nd, 2016

An Archimedes' screw for groups of quantum particles November 19th, 2016

Trickling electrons: Close to absolute zero, the particles exhibit their quantum nature November 10th, 2016

Superconductivity

Quantum obstacle course changes material from superconductor to insulator December 1st, 2016

Scientists shrink electron gun to matchbox size: Terahertz technology has the potential to enable new applications November 25th, 2016

Chip Technology

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Construction of practical quantum computers radically simplified: Scientists invent ground-breaking new method that puts quantum computers within reach December 5th, 2016

Memory Technology

New technology of ultrahigh density optical storage researched at Kazan University: The ever-growing demand for storage devices stimulates scientists to find new ways of improving the performance of existing technologies November 30th, 2016

A Tiny Machine: UCSB electrical and computer engineers design an infinitesimal computing device October 28th, 2016

How nanoscience will improve our health and lives in the coming years: Targeted medicine deliveries and increased energy efficiency are just two of many ways October 26th, 2016

Making the switch, this time with an insulator: Colorado State University physicists, joining the fundamental pursuit of using electron spins to store and manipulate information, have demonstrated a new approach to doing so, which could prove useful in the application of low-powe September 2nd, 2016

Discoveries

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Fast, efficient sperm tails inspire nanobiotechnology December 5th, 2016

Announcements

In IEDM 2016 Keynote, Leti CEO Says ‘Hyperconnectivity’, Human-focused Research and the IOT Promise Profound, Positive Changes December 7th, 2016

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Tools

Deep insights from surface reactions: Researchers use Stampede supercomputer to study new chemical sensing methods, desalination and bacterial energy production December 2nd, 2016

Controlled electron pulses November 30th, 2016

Scientists shrink electron gun to matchbox size: Terahertz technology has the potential to enable new applications November 25th, 2016

News from Quorum: The Agricultural Research Service of the USDA uses a Quorum Cryo-SEM preparation system for the study of mites, ticks and other soft bodied organisms November 22nd, 2016

Quantum nanoscience

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Shape matters when light meets atom: Mapping the interaction of a single atom with a single photon may inform design of quantum devices December 4th, 2016

Trickling electrons: Close to absolute zero, the particles exhibit their quantum nature November 10th, 2016

Scientists set traps for atoms with single-particle precision: Technique may enable large-scale atom arrays for quantum computing November 7th, 2016

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