Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > A Deeper Look at Interfaces: Researchers at Berkeley Lab’s 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 Lab’s 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 “Momentum-resolved electronic structure at a buried interface from soft X-ray standing-wave angle-resolved photoemission.” 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 Lab’s Advanced Light Source go here:

For more about NCEM go here:

Related News Press

News and information

Protein Building Blocks for Nanosystems: Scientists develop method for producing bio-based materials with new properties April 17th, 2015

Oxford Instruments commissions high field outsert magnet system for the National High Magnetic Field Laboratory 32 Tesla magnet program April 17th, 2015

QD Vision Expands Product Line with Two-Millimeter Color LCD Display Optic: Color IQ™ Optic Enables Full-Color Gamut for Ultra-Thin Displays and All-in-One Computers April 16th, 2015

The National Science Foundation names engineering researcher Andrea Alú its Alan T. Waterman awardee for 2015: Alú is a pioneer in the field of metamaterials who has developed "cloaking" technology to make objects invisible to sensors April 16th, 2015

Superconductivity

Unraveling the origin of the pseudogap in a charge density wave compound April 8th, 2015

Frustrated magnets -- new experiment reveals clues to their discontent April 4th, 2015

A first glimpse inside a macroscopic quantum state March 28th, 2015

Using magnetic fields to understand high-temperature superconductivity: Los Alamos explores experimental path to potential 'next theory of superconductivity' March 27th, 2015

Govt.-Legislation/Regulation/Funding/Policy

Oxford Instruments commissions high field outsert magnet system for the National High Magnetic Field Laboratory 32 Tesla magnet program April 17th, 2015

The National Science Foundation names engineering researcher Andrea Alú its Alan T. Waterman awardee for 2015: Alú is a pioneer in the field of metamaterials who has developed "cloaking" technology to make objects invisible to sensors April 16th, 2015

Long Island Capital Alliance Announces Participants for Brookhaven National Laboratory Technology Transfer Capital Forum on May 8: Keynote Speaker Dr. Doon Gibbs, Director of Brookhaven National Laboratory April 16th, 2015

Major advance in artificial photosynthesis poses win/win for the environment: Berkeley Lab researchers perform solar-powered green chemistry with captured CO2 April 16th, 2015

Spintronics

On the road to spin-orbitronics: Berkeley Lab researchers find new way to manipulate magnetic domain walls April 13th, 2015

Graphene looking promising for future spintronic devices April 10th, 2015

Magnetic vortices in nanodisks reveal information: Researchers from Dresden and Jülich use microwaves to read out information from smallest storage devices March 4th, 2015

Insight into inner magnetic layers: Measurements at BESSY II have shown how spin filters forming within magnetic sandwiches influence tunnel magnetoresistance -- results that can help in designing spintronic component- February 17th, 2015

Chip Technology

Nanotubes with two walls have singular qualities: Rice University lab calculates unique electronic qualities of double-walled carbon nanotubes April 16th, 2015

Graphenea embarks on a new era April 16th, 2015

Quantization of 'surface Dirac states' could lead to exotic applications April 15th, 2015

Study shows novel pattern of electrical charge movement through DNA April 14th, 2015

Discoveries

Protein Building Blocks for Nanosystems: Scientists develop method for producing bio-based materials with new properties April 17th, 2015

Major advance in artificial photosynthesis poses win/win for the environment: Berkeley Lab researchers perform solar-powered green chemistry with captured CO2 April 16th, 2015

Newly-Developed Nanocatalysts Increase Performance of Fuel Cells April 16th, 2015

Lanthanide-Organic Framework Nanothermometers Prepared by Spray-Drying April 16th, 2015

Materials/Metamaterials

The National Science Foundation names engineering researcher Andrea Alú its Alan T. Waterman awardee for 2015: Alú is a pioneer in the field of metamaterials who has developed "cloaking" technology to make objects invisible to sensors April 16th, 2015

Cobalt film a clean-fuel find: Rice University discovery is efficient, robust at drawing hydrogen and oxygen from water April 15th, 2015

Combined effort for structural determination April 15th, 2015

Harvesting energy from electromagnetic waves: In the future, clean alternatives such as harvesting energy from electromagnetic waves may help ease the world's energy shortage April 15th, 2015

Announcements

Protein Building Blocks for Nanosystems: Scientists develop method for producing bio-based materials with new properties April 17th, 2015

Oxford Instruments commissions high field outsert magnet system for the National High Magnetic Field Laboratory 32 Tesla magnet program April 17th, 2015

Newly-Developed Nanocatalysts Increase Performance of Fuel Cells April 16th, 2015

Lanthanide-Organic Framework Nanothermometers Prepared by Spray-Drying April 16th, 2015

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

The National Science Foundation names engineering researcher Andrea Alú its Alan T. Waterman awardee for 2015: Alú is a pioneer in the field of metamaterials who has developed "cloaking" technology to make objects invisible to sensors April 16th, 2015

Major advance in artificial photosynthesis poses win/win for the environment: Berkeley Lab researchers perform solar-powered green chemistry with captured CO2 April 16th, 2015

Newly-Developed Nanocatalysts Increase Performance of Fuel Cells April 16th, 2015

Nanotubes with two walls have singular qualities: Rice University lab calculates unique electronic qualities of double-walled carbon nanotubes April 16th, 2015

Tools

Oxford Instruments commissions high field outsert magnet system for the National High Magnetic Field Laboratory 32 Tesla magnet program April 17th, 2015

Lanthanide-Organic Framework Nanothermometers Prepared by Spray-Drying April 16th, 2015

Combined effort for structural determination April 15th, 2015

JPK reports on the use of the NanoWizard® 3 AFM system at the Hebrew University of Jerusalem April 14th, 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







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE