Nanoscale mechanical switching of ferroelectric polarization via flexoelectricity

Journal Article · Mon Jan 12 04:00:00 EST 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4905837· OSTI ID:22399120

Gu, Yijia; Hong, Zijian; Britson, Jason; Chen, Long-Qing ^[1]

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1. Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

Flexoelectric coefficient is a fourth-rank tensor arising from the coupling between strain gradient and electric polarization and thus exists in all crystals. It is generally ignored for macroscopic crystals due to its small magnitude. However, at the nanoscale, flexoelectric contributions may become significant and can potentially be utilized for device applications. Using the phase-field method, we study the mechanical switching of electric polarization in ferroelectric thin films by a strain gradient created via an atomic force microscope tip. Our simulation results show good agreement with existing experimental observations. We examine the competition between the piezoelectric and flexoelectric effects and provide an understanding of the role of flexoelectricity in the polarization switching. Also, by changing the pressure and film thickness, we reveal that the flexoelectric field at the film bottom can be used as a criterion to determine whether domain switching may happen under a mechanical force.

• OSTI ID: 22399120
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 2 Vol. 106; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMIC FORCE MICROSCOPY
COMPUTERIZED SIMULATION
COUPLING
CRYSTALS
FERROELECTRIC MATERIALS
NANOSTRUCTURES
PIEZOELECTRICITY
POLARIZATION
POTENTIALS
STRAINS
TENSORS
THIN FILMS