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.
“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 reports about: > 3-D > Energy Research > Materials Sciences > Nature Communications > Scientific Computing > atomic resolution > basic research > boron nitride > electric field > electronic properties > materials > properties > scanning tunneling microscopy > tunneling > two-dimensional materials
Move over, Superman! NIST method sees through concrete to detect early-stage corrosion
27.04.2017 | National Institute of Standards and Technology (NIST)
Control of molecular motion by metal-plated 3-D printed plastic pieces
27.04.2017 | Ecole Polytechnique Fédérale de Lausanne
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
27.04.2017 | Life Sciences
27.04.2017 | Physics and Astronomy
27.04.2017 | Earth Sciences