New Functional Topological Defect Discovered

Research Highlight

New Functional Topological Defect Discovered

August 7, 2020

Piezoresponse force microscopy detects the co-existence of ferroelectric (FE) and antiferroelectric (AFE) phases in CuInP2S6. Piezoelectricity is enhanced at phase boundaries, creating a topological defect that is simultaneously electromechanically active, originates from a phase boundary, and functions as a polar domain wall.

Scientific Achievement

Piezoelectric domain walls, absent in conventional ferroelectrics, were detected in layered CuInP2Se6 crystals, signaling rare co-existence of ferro- and antiferroelectric phases in the same material.

Significance and Impact

Piezoelectricity now joins an expanding range of functionalities exhibited by domain walls, leading to new device prospects utilizing the control of materials by applied fields.

Research Details

– Domain walls typically exhibit zero piezoresponse. CuInP₂Se₆ revealed the opposite with the largest piezoresponse localized to domain walls. – Quantitative microscopy combined with theory and optical spectroscopy revealed co-existence of ferroelectric and antiferroelectric states, not observed previously. – Phase co-existence can be controlled by applied fields. Andrius Dziaugys, Kyle Kelley, John A. Brehm, Lei Tao3, 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, and Petro Maksymovych,"Piezoelectric domain walls in van der Waals antiferroelectric CuInP₂Se₆," Nature Communications (2020).