Abstract
The dependence of electromechanical behavior on strain in ferroelectric materials can be leveraged as parameter to tune ferroelectric properties such as the Curie temperature. For van der Waals materials, a unique opportunity arises because of wrinkling, bubbling, and Moiré phenomena accessible due to structural properties inherent to the van der Waals gap. Here, we use piezoresponse force microscopy and unsupervised machine learning methods to gain insight into the ferroelectric properties of layered CuInP2S6 where local areas are strained in-plane due to a partial delamination, resulting in a topographic bubble feature. We observe significant differences between strained and unstrained areas in piezoresponse images as well as voltage spectroscopy, during which strained areas show a sigmoid-shaped response usually associated with the response measured around the Curie temperature, indicating a lowering of the Curie temperature under tensile strain. These results suggest that strain engineering might be used to further increase the functionality of CuInP2S6 through locally modifying ferroelectric properties on the micro- and nanoscale.
Original language | English |
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Article number | 9138775 |
Pages (from-to) | 253-258 |
Number of pages | 6 |
Journal | IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control |
Volume | 68 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2021 |
Funding
Manuscript received April 27, 2020; accepted July 1, 2020. Date of publication July 10, 2020; date of current version January 26, 2021. The ferroelectric characterization and sample synthesis were supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. The experiments were conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. A portion of the writing of this article was funded by the Air Force Office of Scientific Research under Grant LRIR #19RXCOR052 and by the Department of Energy, Basic Energy Sciences, Materials Science and Engineering Division under Award #DE-FG02-09ER46554. (Corresponding author: Nina Balke.) Sabine M. Neumayer, Petro Maksymovych, and Nina Balke are with the Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA (e-mail: neumayersm. . nl.gov; maksymovychp. . nl.gov; balken. . nl.gov).
Keywords
- Ferroelectric
- piezoelectric
- strain engineering
- van der Waals material