Unlocking the Electrical Potential of 1D InterfacesColby Hochmuth | November 20, 2014
A recent study by the Oak Ridge National Laboratory has, reporetdly for the first time, made direct observations of a one-dimensional boundary separating two different, atom-thin materials.
Scientists have realized a number of possibilities this discovery presents for engineering, especially its electrical capabilities. The team says the 1D chain of electrons could be useful for electronics, especially ultra-thin or flexible devices.
This new study, “Spatially resolved one-dimensional boundary states in graphene–hexagonal boron nitride planar heterostructures,” builds on work published by scientists at the University of Tennessee and ORNL earlier in the year that introduced a way to grow different two-dimensional materials—boron nitride and grapheme—into a single, one-atom-thick layer.
The ORNL team’s materials growth technique exposed the ability to study the 1D boundary and its electronic properties in atomic resolution, according to ORNL. Researchers were able to obtain a first comprehensive picture of energetic and spatial distributions of the 1D interface states by using spectroscopy, microscopy and density-functional calculations.
“In three-dimensional 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,” says Jewook Park, ORNL postdoctoral researcher and the lead author of the work.
“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,” says ORNL’s Mina Yoon, a theorist on the team.
This development may also mean new advances for nanotechnology and electronic devices. According to ORNL, in addition to its potential use for electronics, the researchers also plan to continue looking into different aspects of the boundary, including its magnetic properties and the effect of its supporting substrate.
Among those observations, researchers also found that the highly confined electric field at the interface provided an opportunity to investigate “polar catastrophe,” described by ORNL as an “intriguing phenomenon.” Polar catastrophe can cause atomic and electron reorganization at the interface to compensate for the electrostatic field that results from materials’ different polarities, ORNL says.
The research was supported by the Energy Department’s Office of Science, ORNL’s Laboratory Directed Research and Development program, the National Science Foundation and the Defense Advances Research Projects Agency (DARPA) and 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.