2018/03/31 by Sabine M. Neumayer, Eugene A. Eliseev, Michael A. Susner +11 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #2D Materials and Applications #Dielectric #Dielectric materials and actuators #Electrostriction #Ferroelectric and Piezoelectric Materials #Ferroelectricity #Flexoelectricity #Indium #Piezoelectric coefficient #Piezoelectricity #cond-mat.mtrl-sci #van der Waals force
paper · pdf · doi:10.1103/physrevmaterials.3.024401
published as Phys. Rev. Materials 3, 024401 (2019) · Published version in Phys. Rev. Materials https://journals.aps.org/prmaterials/abstract/10.1103/PhysRevMaterials.3.024401
openalex created_date 2018/03/29 · arxiv created 2019/02/01 · openalex publication_date 2019/02/01 · arxiv updated 2019/02/04 · openalex updated_date 2026/08/06
The interest in ferroelectric van der Waals crystals arises from the potential to realize ultrathin ferroic systems owing to the reduced surface energy of these materials and the layered structure that allows for exfoliation. Here, we quantitatively unravel giant negative electrostriction of van der Waals layered copper indium thiophosphate (CIPS), which exhibits an electrostrictive coefficient Q33 as high as \ensuremath-3.2\phantom\rule0.16em0exm4/C2 and a resulting bulk piezoelectric coefficient d33 up to \ensuremath-85 pm/V. As a result, the electromechanical response of CIPS is comparable in magnitude to established perovskite ferroelectrics despite possessing a much smaller spontaneous polarization of only a few \ensuremathμC/cm2. In the paraelectric state, readily accessible owing to low transition temperatures, CIPS exhibits large dielectric tunability, similar to widely used barium strontium titanate, and as a result both giant and continuously tunable electromechanical response. The persistence of electrostrictive and tunable responses in the paraelectric state indicates that even few-layer films or nanoparticles will sustain significant electromechanical functionality, offsetting the inevitable suppression of ferroelectric properties in the nanoscale limit. These findings can likely be extended to other ferroelectric transition metal thiophosphates and (quasi-) two-dimensional materials, and might facilitate the quest toward alternative ultrathin functional devices incorporating electromechanical response.