| AVS 65th International Symposium & Exhibition | |
| 2D Materials Focus Topic | Thursday Sessions |
| Session 2D+EM+MN+NS-ThA |
| Session: | Novel Quantum Phenomena in 2D Materials |
| Presenter: | Sabine Neumayer, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory |
| Authors: | S. Neumayer, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory E.A. Eliseev, National Academy of Sciences of Ukraine A. Tselev, CICECO and Department of Physics, University of Aveiro, Portugal A.N. Morozovska, National Academy of Sciences of Ukraine M.A. Susner, Oak Ridge National Laboratory M.A. McGuire, Oak Ridge National Laboratory J. Brehm, Vanderbilt University S. Pantelides, Vanderbilt University N. Balke, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory P. Maksymovych, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
Obtaining ultrathin electromechanically active materials for memory and energy applications encounters numerous challenges as significant downscaling of classical ferroelectrics such as perovskite oxides is severely constrained by size and screening effects. Moreover, interfacing pseudo-cubic ferroelectrics with 2D electronic materials faces challenges related to defect and impurities, which limit performance. Van der Waals ferroelectrics, especially transition metal thiophosphates such as copper indium thiophosphate (CIPS) yield promising prospects for applications as ultrathin piezoelectric structures and interface materials due to their stable surfaces, layered structure and transition temperatures near room temperature. Here, we use scanning probe microscopy to explore the remarkable functional properties of CIPS across the transition temperature. At low temperatures, strong electromechanical response is measured despite the small polarization values and the material contracts in electric fields rather than expanding. These findings point to giant negative electrostrictive coefficients, which were quantified using Landau-Ginzburg-Devonshire analysis. Above the transition temperature, CIPS shows dielectric tunability comparable to BST at low frequencies. In addition, electromechanical strain exceeding 10 nm displacement was measured upon fully reversible field induced formation of particles on the surface. Complimentary DFT calculations provide further insight into the role of ionic displacement in electromechanical behavior.
Research conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility . Research was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy.