Piezoelectric domain walls in van der Waals ferroelectric CuInP<sub>2</sub>Se<sub>6</sub>
POSTER
Abstract
Van der Waals layered chalcogenophosphates, such as CuInP2S6 and AgInP2S6, exhibit intriguing polar properties such as room temperature ferrielectric ordering, negative electrostriction, large elastic nonlinearity, proximity to ionic conductivity and multi-well ferroelectric potential, presumably due to a unique influence of the van der Waals gap. Here we will discuss anomalous properties of domain walls in ferrielectric selenophosphate CuInP2Se6 detected using piezoresponse force microscopy. Whereas in ferroelectrics, including a structurally similar case of ferrielectric CuInP2S6, electromechanical response and polarization vanish at the domain wall, the reverse is true in the case of CuInP2Se6, so that piezoresponse vanishes everywhere but the domain wall. And yet, these domain walls can be manipulated by electric field. We propose the existence of an antiferroelectric phase in the near-surface layer of CuInP2Se6, with locally enhanced polarization at antiferroelectric domain walls. Nature Comms. in review (2019).
*Experiments carried out at the Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, with addition support from CIEE / Baltic-American Freedom Foundation, DOE MSE at ORNL and University of Vanderbilt.
Presenters
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Petro Maksymovych
- Center for Nanophase Materials Sciences, Oak Ridge National Lab
- Oak Ridge National Lab
- Oak Ridge National Laboratory