Researchers at the Department of Energy's Oak Ridge National Laboratory have developed a new method to manipulate a wide range of materials and their behavior using only a handful of helium ions.
The team's technique, published in Physical Review Letters, advances the understanding and use of complex oxide materials that boast unusual properties such as superconductivity and colossal magnetoresistance but are notoriously difficult to control.
For the first time, ORNL researchers have discovered a simple way to control the elongation of a crystalline material along a single direction without changing the length along the other directions or damaging the crystalline structure. This is accomplished by adding a few helium ions into a complex oxide material and provides a never before possible level of control over magnetic and electronic properties.
"By putting a little helium into the material, we're able to control strain along a single axis," said ORNL's Zac Ward, who led the team's study. "This type of control wasn't possible before, and it allows you to tune material properties with a finesse that we haven't previously had access to."
The intricate way in which electrons are bound inside complex oxides means that any strain -- stretching, pulling or pushing of the structure -- triggers changes in many different electronic properties. This ripple effect complicates scientists' ability to study or make use of the finicky materials.
The researchers demonstrated the technique on a common oxide material known as LSMO but they anticipate the technique will be widely applicable to both functionality driven materials science research and fundamental physics studies.
"Complex oxides are where we expect an immediate impact, but this technique should be an important new tool to use on any material where crystal symmetry affects functionality," Ward said.
The team's work is a step toward bringing complex materials into commercial applications, which would greatly benefit from the ability to tune material properties with processing similar to current semiconductor technologies.
"Our strain doping technique demonstrates a path to achieving this need, as it can be implemented using established ion implantation infrastructure in the semiconductor industry," Ward said.
The method uses a low-energy ion gun to add small numbers of helium ions into the material after it has been produced. The process is also reversible; the helium can be removed by heating the material to high temperatures in vacuum. Previously developed strain tuning methods modify all directions in a material and cannot be altered or reversed afterwards.
"We can easily control the amount of strain and how deep that strain is inside the material," Ward said. "By controlling the number of helium atoms inserted into an epitaxial film, we select a strain state in one direction while the other two directions are held in place by the substrate."
The team's experimental technique will also benefit theoretical research that seeks to model complex materials to predict and understand their behavior.
"The complexity of these materials requires a huge equation to explain their behaviors," Ward said. "Normal strain tuning methods require you to change many variables in that equation which means that you don't really know which one is giving you a specific reaction. In our case, there's one variable. You can feed in a single term and try to break through that complexity a little bit by simplifying it. This is a great method to experimentally probe theoretical models."
The paper is published as "Strain doping: Reversible single axis control of a complex oxide lattice via helium implantation." Coauthors are ORNL's Hangwen Guo, Shuai Dong, Philip Rack, John Budai, Christianne Beekman, Zheng Gai, Wolter Siemons, C.M. Gonzalez, R. Timilsina, Anthony Wong, Andreas Herklotz, Paul Snijders, Elbio Dagotto and Thomas Ward.
The study was supported by the Department of Energy's Office of Science and used resources at the Center for Nanophase Materials Sciences, a DOE Office of Science User Facility at ORNL.
UT-Battelle manages ORNL for the Department of Energy's Office of Science. The 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.
Morgan McCorkle | EurekAlert!
Further reports about: > Helium > Laboratory > ORNL > Physical Review Letters > ability > crystalline > electronic properties > elongation > equation > helium atoms > inside > ions > material > material properties > materials > methods > oxide materials > properties > semiconductor > strain > structure
Researchers demonstrate existence of new form of electronic matter
15.03.2018 | University of Illinois at Urbana-Champaign
Boron can form a purely honeycomb, graphene-like 2-D structure
15.03.2018 | Science China Press
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.
Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...
16.03.2018 | Event News
13.03.2018 | Event News
08.03.2018 | Event News
16.03.2018 | Earth Sciences
16.03.2018 | Physics and Astronomy
16.03.2018 | Life Sciences