Ferroelectric materials, which switch their polarization with the application of an electric field, have long been used in devices such as ultrasound machines and sensors. Now, discoveries about ferroelectrics' electronic properties are opening up possibilities of applications in nanoscale electronics and information storage.
ORNL researchers used piezoresponse force microscopy to demonstrate the first evidence of metallic conductivity in ferroelectric nanodomains. A representative nanodomain is shown in the PFM image above.
In a paper published in the American Chemical Society's Nano Letters, the ORNL-led team demonstrated metallic conductivity in a ferroelectric film that otherwise acts as an insulator. This phenomenon of an insulator-metal transition was predicted more than 40 years ago by theorists but has eluded experimental proof until now.
"This finding unambiguously identifies a new conduction channel that percolates through the insulating matrix of the ferroelectric, which opens potentially exciting possibilities to 'write' and 'erase' circuitry with nanoscale dimensions," said lead author Peter Maksymovych of ORNL's Center for Nanophase Materials Sciences.
From an applied perspective, the ability to use only an electric field as a knob that tunes both the magnitude of metallic conductivity in a ferroelectric and the type of charge carriers is particularly intriguing. Doing the latter in a semiconductor would require a change of the material composition.
"Not only can we turn on metallic conductivity, but if you keep changing the bias dials, you can control the behavior very precisely," Maksymovych said. "And the smaller the nanodomain, the better it conducts. All this occurs in the exact same position of the material, and we can go from an insulator to a better metal or a worse metal in a heartbeat or faster. This is potentially attractive for applications, and it also leads to interesting fundamental questions about the exact mechanism of metallic conductivity."
Although the researchers focused their study on a well-known ferroelectric film called lead-zirconate titanate, they expect their observations will hold true for a broader array of ferroelectric materials.
"We also anticipate that extending our studies onto multiferroics, mixed-phase and anti-ferroelectrics will reveal a whole family of previously unknown electronic properties, breaking new ground in fundamentals and applications alike," said co-author and ORNL senior scientist Sergei Kalinin.
The samples used in the study were provided by the University of California at Berkeley. Co-authors on the paper are ORNL's Arthur Baddorf, UC Berkeley's Ying-Hao Chu, Ramamoorthy Ramesh and Pu Yu, and National Academy of Science of Ukraine's Eugene Eliseev and Anna Morozovska. The full paper, "Tunable Metallic Conductance in Ferroelectric Nanodomains," is available at http://pubs.acs.org/doi/full/10.1021/nl203349b.
Part of this work was supported by the Center for Nanophase Materials Sciences at ORNL. CNMS is one of the five DOE Nanoscale Science Research Centers supported by the DOE Office of Science, premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos national laboratories. For more information about the DOE NSRCs, please visit http://science.energy.gov/bes/suf/user-facilities/nanoscale-science-research-centers/. Work at the University of California, Berkeley, was supported by DOE's Office of Science and the Semiconductor Research Corporation. ORNL is managed by UT-Battelle for the Department of Energy's Office of Science.
Morgan McCorkle | EurekAlert!
Plumbene, graphene's latest cousin, realized on the 'nano water cube'
23.05.2019 | Nagoya University
New flatland material: Physicists obtain quasi-2D gold
23.05.2019 | Moscow Institute of Physics and Technology
Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.
The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...
Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...
With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.
Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...
'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.
However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...
Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future
When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
23.05.2019 | Materials Sciences
23.05.2019 | Materials Sciences
23.05.2019 | Physics and Astronomy