Flexoelectricity offers an energy harvesting alternative to piezoelectric materials. Although flexoelectricity is
generally weak in most materials, recent findings show that bending a semiconductor with insulating barrier layers could induce a significantly enhanced flexoelectric response. We call this effect the Space Charge Induced Flexoelectric (SCIF) effect. This study explores the induced polarization resulting from free charge
redistribution in a doped silicon beam. To understand the underlying physics, a 3D numerical model combining flexoelectric principles and the drift-diffusion theory of semiconduction was developed. The effective flexoelectric coefficient was computed by comparing the differential charge accumulation at the top and bottom of the beam and compared that with the experimental observations.
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This content will become publicly available on March 25, 2025
Polarization near dislocation cores in SrTiO3 single crystals: The role of flexoelectricity
Spontaneous polarization as large as ∼28 μC/cm2 was recently observed around the dislocation cores in non-polar SrTiO3 bulk crystals, and its origin was attributed to the flexoelectric effect, i.e., polarization induced by strain gradients. However, the roles of flexoelectricity, relative to other electromechanical contributions, and the nature of dislocations, i.e., edge vs screw dislocations in the induced polarization, are not well understood. In this work, we study the role of flexoelectricity in inducing polarization around three types of dislocation cores in SrTiO3: b=a(100) edge dislocation, b=a(110) edge dislocation, and b=a(010) screw dislocation, where b is the Burgers vector. For the edge dislocations, polarization can be induced by electrostriction alone, while flexoelectricity is essential for stabilizing the symmetric polarization pattern. The shear component of the flexoelectric tensor has a dominant effect on the magnitude and spatial distribution of the flexoelectric polarization. In contrast, no polarization is induced around the b=a(010) screw dislocation through either electrostriction or flexoelectricity. Our findings provide an in-depth understanding of the role of flexoelectricity in inducing polarization around dislocation cores and offer insights into the defect engineering of dielectric/ferroelectric materials.
more » « less- Award ID(s):
- 2133373
- PAR ID:
- 10537153
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- Applied Physics Letters
- Volume:
- 124
- Issue:
- 13
- ISSN:
- 0003-6951
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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