Abstract: Polar van der Waals chalcogenophosphates exhibit unique properties, such as negative electrostriction and multi-well ferrielectricity, and enable combining dielectric and 2D electronic materials. Using low temperature piezoresponse force microscopy, we revealed coexistence of piezoelectric and non-piezoelectric phases in CuInP2Se6, forming unusual domain walls with enhanced piezoelectric response. From systematic imaging experiments we have inferred the formation of a partially polarized antiferroelectric state, with inclusions of structurally distinct ferrielectric domains enclosed by the corresponding phase boundaries. The assignment is strongly supported by optical spectroscopies and density-functional-theory calculations. Enhanced piezoresponse at the ferrielectric/antiferroelectric phase boundary and the ability to manipulate this entity with electric field on the nanoscale expand the existing phenomenology of functional domain walls. At the same time, phase-coexistence in chalcogenophosphates may lead to rational strategies for incorporation of ferroic functionality into van der Waals heterostructures, with stronger resilience toward detrimental size-effects.
Title: Piezoelectric domain walls in van der Waals antiferroelectric CuInP2Se6
Authors: Andrius Dziaugys, Kyle Kelley, John A. Brehm, Lei Tao, Alexander Puretzky, Tianli Feng, Andrew O’Hara, Sabine Neumayer, Marius Chyasnavichyus, Eugene A. Eliseev, Juras Banys, Yulian Vysochanskii, Feng Ye, Bryan C. Chakoumakos, Michael A. Susner, Michael A. McGuire, Sergei V. Kalinin, Panchapakesan Ganesh, Nina Balke, Sokrates T. Pantelides, Anna N. Morozovska, Petro Maksymovych
DOI: https://doi.org/10.1038/s41467-020-17137-0 Nature Communications (2020) 11, 3623
Preprint/Postprint: OPEN ACCESS