Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

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

Democratizing synthetic biology: New method makes research cheaper, faster, and more accessible March 3rd, 2015

Pens filled with high-tech inks for do-it-yourself sensors March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Heightened Efficiency in Purification of Wastewater Using Nanomembranes March 3rd, 2015

Superconductivity

Warming up the world of superconductors: Clusters of aluminum metal atoms become superconductive at surprisingly high temperatures February 25th, 2015

Ultra-thin nanowires can trap electron 'twisters' that disrupt superconductors February 24th, 2015

Simulating superconducting materials with ultracold atoms: Rice physicists build superconductor analog, observe antiferromagnetic order February 23rd, 2015

Bar-Ilan U. researcher first to observe 'god particle' analogue in superconductors: Introduces 'tabletop' technique for examining the standard model of physics' most celebrated missing link February 19th, 2015

Govt.-Legislation/Regulation/Funding/Policy

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

New nanodevice defeats drug resistance: Tiny particles embedded in gel can turn off drug-resistance genes, then release cancer drugs March 2nd, 2015

Forbidden quantum leaps possible with high-res spectroscopy March 2nd, 2015

Researchers turn unzipped nanotubes into possible alternative for platinum: Aerogel catalyst shows promise for fuel cells March 2nd, 2015

Spintronics

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

A new spin on spintronics: Michigan team tests radiation-resistant spintronic material, possibly enabling electronic devices that will work in harsh environments February 17th, 2015

Nanoscale Mirrored Cavities Amplify, Connect Quantum Memories: Advance could lead to quantum computing and the secure transfer of information over long-distance fiber optic networks January 28th, 2015

Piezoelectricity in a 2-D semiconductor: Berkeley Lab researchers discovery of piezoelectricty in molybdenum disulfide holds promise for future MEMS December 22nd, 2014

Chip Technology

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

International research partnership tricks the light fantastic March 2nd, 2015

Important step towards quantum computing: Metals at atomic scale March 2nd, 2015

onic Present breakthrough in CMOS-based Transceivers for mm-Wave Radar Systems March 1st, 2015

Discoveries

Democratizing synthetic biology: New method makes research cheaper, faster, and more accessible March 3rd, 2015

Pens filled with high-tech inks for do-it-yourself sensors March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Heightened Efficiency in Purification of Wastewater Using Nanomembranes March 3rd, 2015

Materials/Metamaterials

Breakthrough in OLED technology March 2nd, 2015

Moving molecule writes letters: Caging of molecules allows investigation of equilibrium thermodynamics February 27th, 2015

Graphene shows potential as novel anti-cancer therapeutic strategy: University of Manchester scientists have used graphene to target and neutralise cancer stem cells while not harming other cells February 26th, 2015

Learning by eye: Silicon micro-funnels increase the efficiency of solar cells February 25th, 2015

Announcements

Democratizing synthetic biology: New method makes research cheaper, faster, and more accessible March 3rd, 2015

Pens filled with high-tech inks for do-it-yourself sensors March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Heightened Efficiency in Purification of Wastewater Using Nanomembranes March 3rd, 2015

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

Democratizing synthetic biology: New method makes research cheaper, faster, and more accessible March 3rd, 2015

Pens filled with high-tech inks for do-it-yourself sensors March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Heightened Efficiency in Purification of Wastewater Using Nanomembranes March 3rd, 2015

Tools

Forbidden quantum leaps possible with high-res spectroscopy March 2nd, 2015

International research partnership tricks the light fantastic March 2nd, 2015

Important step towards quantum computing: Metals at atomic scale March 2nd, 2015

Mass spectrometers with optimised hydrogen pumping March 1st, 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