Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

ORNL materials researchers get first look at atom-thin boundaries

11.11.2014

Scientists at the Department of Energy’s Oak Ridge National Laboratory have made the first direct observations of a one-dimensional boundary separating two different, atom-thin materials, enabling studies of long-theorized phenomena at these interfaces.

Theorists have predicted the existence of intriguing properties at one-dimensional (1-D) boundaries between two crystalline components, but experimental verification has eluded researchers because atomically precise 1-D interfaces are difficult to construct.


Scientists at the Oak Ridge National Laboratory have made the first direct observations of the electronic behaviors of a one-dimensional boundary separating atom-thin graphene and hexagonal boron nitride materials.

“While many theoretical studies of such 1-D interfaces predict striking behaviors, in our work we have provided the first experimental validation of those interface properties,” said ORNL’s An-Ping Li.

The new Nature Communications study builds on work by ORNL and University of Tennessee scientists published in Science earlier this year that introduced a method to grow different two-dimensional materials – graphene and boron nitride – into a single layer only one atom thick.

The team’s materials growth technique unlocked the ability to study the 1-D boundary and its electronic properties in atomic resolution. Using scanning tunneling microscopy, spectroscopy and density-functional calculations, the researchers first obtained a comprehensive picture of spatial and energetic distributions of the 1-D interface states.

“In three-dimensional (3-D) systems, the interface is embedded so you cannot get a real-space view of the complete interface – you can only look at a projection of that plane,” said Jewook Park, ORNL postdoctoral researcher and the lead author of the work. “In our case, the 1-D interface is completely accessible to real-space study,”

“The combination of scanning tunneling microscopy and the first principles theory calculations allows us to distinguish the chemical nature of the boundary and evaluate the effects of orbital hybridization at the junction,” said ORNL’s Mina Yoon, a theorist on the team.

The researchers’ observations revealed a highly confined electric field at the interface and provided an opportunity to investigate an intriguing phenomenon known as a “polar catastrophe,” which occurs in 3-D oxide interfaces. This effect can cause atomic and electron reorganization at the interface to compensate for the electrostatic field resulting from materials’ different polarities.

“This is the first time we have been able to study the polar discontinuity effect in a 1-D boundary,” Li said.

Although the researchers focused on gaining a fundamental understanding of the system, they note their study could culminate in applications that take advantage of the 1-D interface.

“For instance, the 1-D chain of electrons could be exploited to pass a current along the boundary,” Li said. “It could be useful for electronics, especially for ultra-thin or flexible devices.”

The team plans to continue examining different aspects of the boundary including its magnetic properties and the effect of its supporting substrate.

The study is published as “Spatially resolved one-dimensional boundary states in graphene–hexagonal boron nitride planar heterostructures.” Coauthors are ORNL’s Jewook Park, Jaekwang Lee, Corentin Durand, Changwon Park, Bobby Sumpter, Arthur Baddorf, Mina Yoon and An-Ping Li; the University of Tennessee’s Lei Liu, Ali Mohsin, and Gong Gu; and Central Methodist University’s Kendal Clark.

This research was conducted in part at the Center for Nanophase Materials Sciences and the National Energy Research Scientific Computing Center, both DOE Office of Science User Facilities. The research was supported by DOE’s Office of Science, ORNL’s Laboratory Directed Research and Development program, the National Science Foundation and DARPA.

ORNL is managed by UT-Battelle for the Department of Energy's Office of Science. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov

Morgan McCorkle | EurekAlert!
Further information:
http://www.ornl.gov/ornl/news/news-releases/2014/ornl-materials-researchers-get-first-look-at-atom-thin-boundaries

More articles from Materials Sciences:

nachricht New material could lead to erasable and rewriteable optical chips
07.12.2016 | University of Texas at Austin

nachricht Porous crystalline materials: TU Graz researcher shows method for controlled growth
07.12.2016 | Technische Universität Graz

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>