Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button

Home > Press > A Deeper Look at Interfaces: Researchers at Berkeley Labís Advanced Light Source Develop New Technique for Probing Subsurface Electronic Structure

Experimental setup and basic principles of SWARPES shows (a) the experimental setup; (b) diagram of the multilayer STO and LSMO film; (c) SW-excited photoemission intensity rocking curves and (d) simulated intensity of the x-ray standing wave field as a function of depth and grazing incidence angle.
Experimental setup and basic principles of SWARPES shows (a) the experimental setup; (b) diagram of the multilayer STO and LSMO film; (c) SW-excited photoemission intensity rocking curves and (d) simulated intensity of the x-ray standing wave field as a function of depth and grazing incidence angle.

Abstract:
"The interface is the device," Nobel laureate Herbert Kroemer famously observed, referring to the remarkable properties to be found at the junctures where layers of different materials meet. In today's burgeoning world of nanotechnology, the interfaces between layers of metal oxides are becoming increasingly prominent, with applications in such high-tech favorites as spintronics, high-temperature superconductors, ferroelectrics and multiferroics. Realizing the vast potential of these metal oxide interfaces, especially those buried in subsurface layers, will require detailed knowledge of their electronic structure.

A Deeper Look at Interfaces: Researchers at Berkeley Labís Advanced Light Source Develop New Technique for Probing Subsurface Electronic Structure

Berkeley, CA | Posted on January 15th, 2014

A new technique from an international team of researchers working at Berkeley Lab's Advanced Light Source (ALS) promises to deliver the goods. In a study led by Charles Fadley, a physicist who holds joint appointments with Berkeley Lab's Materials Sciences Division and the University of California Davis, where he is a Distinguished Professor of Physics, the team combined two well-established techniques for studying electronic structure in crystalline materials into a new technique that is optimized for examining electronic properties at subsurface interfaces. They call this new technique SWARPES, for Standing Wave Angle-Resolved Photoemission Spectroscopy.

"SWARPES allows us for the first time to selectively study buried interfaces with either soft or hard x-rays," Fadley says. "The technique can be applied to any multilayer prototype device structure in spintronics, strongly correlated/high-TC superconductors, or semiconductor electronics. The only limitations are that the sample has to have a high degree of crystalline order, and has to be grown on a nanoscale multilayer mirror suitable for generating an x-ray standing wave."

As the name indicates, SWARPES combines the use of standing waves of x-rays with ARPES, the technique of choice for studying electronic structure. A standing wave is a vibrational pattern created when two waves of identical wavelength interfere with one another: one is the incident x-ray and the other is the x-ray reflected by a mirror. Interactions between standing waves and core-level electrons reveal much about the properties of each atomic species in a sample. ARPES from the outer valence levels is the long-standing spectroscopic workhorse for the study of electronic structure. X-rays striking a material surface or interface cause the photoemission of electrons at angles and kinetic energies that can be measured to obtain detailed electronic energy levels of the sample. While an extremely powerful tool, ARPES, a soft x-ray technique, is primarily limited to the study of near-surface atoms. It's harder x-ray cousin, HARPES, makes use of more energetic x-rays to effectively probe subsurface interfaces, but the addition of the standing wave capability provides a much desired depth selectivity.

"The standing wave can be moved up and down in a sample simply by rocking the angle of incidence around the Bragg angle of the mirror," says Alexander Gray, a former member of Fadley's UC Davis research group and affiliate with Berkeley Lab's Materials Sciences Division, who is now a postdoctoral associate at Stanford/SLAC. "Observing an interface between a ferromagnetic conductor (lanthanum strontium manganite) and an insulator (strontium titanate), which constitute a magnetic tunnel junction used in spintronic logic circuits, we've shown that changes in the electronic structure can be reliably measured, and that these changes are semi-quantitatively predicted by theory at several levels. Our results point to a much wider use of SWARPES in the future for studying the electronic properties of buried interfaces of many different kinds."

Fadley, Gray and their collaborators carried out their SWARPES tests at ALS Beamline 7.0.1. The Advanced Light Source is a U.S. Department of Energy (DOE) national user facility and Beamline 7.0.1 features a premier endstation for determining the electronic structure of metals, semiconductors and insulators. Additional corroborating measurements concerning the interface atomic structure were performed at the National Center for Electron Microscopy (NCEM), another DOE national user facility hosted at Berkeley Lab.

This research was supported primarily by the U.S. Department of Energy (DOE) Office of Science.

####

For more information, please click here

Contacts:
Lynn Yarris

510-486-5375

Copyright © Berkeley Lab

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

Results of this study have been published in Europhysics Letters (EPL). The paper is titled ďMomentum-resolved electronic structure at a buried interface from soft X-ray standing-wave angle-resolved photoemission.Ē Gray was the lead author, Fadley the corresponding author. For a full list of co-authors and their host institutes download the paper here:

For more about the research of Charles Fadley, go here:

For more about Berkeley Labís Advanced Light Source go here:

For more about NCEM go here:

Related News Press

News and information

New microchip demonstrates efficiency and scalable design: Increased power and slashed energy consumption for data centers August 24th, 2016

Tunneling nanotubes between neurons enable the spread of Parkinson's disease via lysosomes August 24th, 2016

New flexible material can make any window 'smart' August 23rd, 2016

University of Puerto Rico and NASA back in the news Ė XEI reports August 23rd, 2016

Superconductivity

Superconductivity: After the scenario, the staging August 20th, 2016

Superconductivity: After the scenario, the staging August 20th, 2016

Scientists uncover origin of high-temperature superconductivity in copper-oxide compound: Analysis of thousands of samples reveals that the compound becomes superconducting at an unusually high temperature because local electron pairs form a 'superfluid' that flows without resist August 19th, 2016

Enhanced electron doping on iron superconductors discovered: IBS Centre for Correlated Electron Systems revises existing theories by raising the temperature for superconductivity August 17th, 2016

Govt.-Legislation/Regulation/Funding/Policy

New theory could lead to new generation of energy friendly optoelectronics: Researchers at Queen's University Belfast and ETH Zurich, Switzerland, have created a new theoretical framework which could help physicists and device engineers design better optoelectronics August 23rd, 2016

New flexible material can make any window 'smart' August 23rd, 2016

Researchers reduce expensive noble metals for fuel cell reactions August 22nd, 2016

Spider silk: Mother Nature's bio-superlens August 22nd, 2016

Spintronics

Swapping substrates improves edges of graphene nanoribbons: Using inert boron nitride instead of silica creates precise zigzag edges in monolayer graphene August 2nd, 2016

Quantum drag:University of Iowa physicist says current in one iron magnetic sheet can create quantized spin waves in another, separate sheet July 22nd, 2016

A mini-antenna for the data processing of tomorrow: Nature Nanotechnology: Short-wavelength spin waves generated directly for the first time July 20th, 2016

A new spin on reality July 15th, 2016

Chip Technology

New microchip demonstrates efficiency and scalable design: Increased power and slashed energy consumption for data centers August 24th, 2016

New theory could lead to new generation of energy friendly optoelectronics: Researchers at Queen's University Belfast and ETH Zurich, Switzerland, have created a new theoretical framework which could help physicists and device engineers design better optoelectronics August 23rd, 2016

Down to the wire: ONR researchers and new bacteria August 18th, 2016

Hexagonal boron nitride semiconductors enable cost-effective detection of neutron signals: Texas Tech University researchers demonstrate hexagonal boron nitride semiconductors as a cost-effective alternative for inspecting overseas cargo containers entering US ports August 17th, 2016

Discoveries

New microchip demonstrates efficiency and scalable design: Increased power and slashed energy consumption for data centers August 24th, 2016

Tunneling nanotubes between neurons enable the spread of Parkinson's disease via lysosomes August 24th, 2016

New theory could lead to new generation of energy friendly optoelectronics: Researchers at Queen's University Belfast and ETH Zurich, Switzerland, have created a new theoretical framework which could help physicists and device engineers design better optoelectronics August 23rd, 2016

New flexible material can make any window 'smart' August 23rd, 2016

Materials/Metamaterials

New flexible material can make any window 'smart' August 23rd, 2016

Researchers reduce expensive noble metals for fuel cell reactions August 22nd, 2016

Industrial Nanotech, Inc. Provides Shareholder Update August 22nd, 2016

Carbodeon Ltd Oy Closes EUR 1.5 million Funding Round From Straightforward Capital: Carbodeon will accelerate its nanodiamonds business and expand manufacturing capacity August 21st, 2016

Announcements

New microchip demonstrates efficiency and scalable design: Increased power and slashed energy consumption for data centers August 24th, 2016

Tunneling nanotubes between neurons enable the spread of Parkinson's disease via lysosomes August 24th, 2016

New flexible material can make any window 'smart' August 23rd, 2016

University of Puerto Rico and NASA back in the news Ė XEI reports August 23rd, 2016

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

New microchip demonstrates efficiency and scalable design: Increased power and slashed energy consumption for data centers August 24th, 2016

Tunneling nanotubes between neurons enable the spread of Parkinson's disease via lysosomes August 24th, 2016

New theory could lead to new generation of energy friendly optoelectronics: Researchers at Queen's University Belfast and ETH Zurich, Switzerland, have created a new theoretical framework which could help physicists and device engineers design better optoelectronics August 23rd, 2016

New flexible material can make any window 'smart' August 23rd, 2016

Tools

University of Puerto Rico and NASA back in the news Ė XEI reports August 23rd, 2016

Spider silk: Mother Nature's bio-superlens August 22nd, 2016

Tracing barnacle's footprint August 19th, 2016

XEI Scientific celebrates its Silver Anniversary August 16th, 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







Car Brands
Buy website traffic