Abstract for an Invited Paper for the MAR09 Meeting of The American Physical Society Flexoelectricity in nanostructures

for an Invited Paper for the MAR09 Meeting of The American Physical Society Flexoelectricity in nanostructures PRADEEP SHARMA, University of Houston Crystalline piezoelectric dielectrics electrically polarize upon application of uniform mechanical strain. Inhomogeneous strain, however, locally breaks inversion symmetry and can potentially polarize even non-piezoelectric (centrosymmetric) dielectrics. Flexoelectricty–the coupling of strain gradient to polarization– is expected to show a strong size-dependency due to the scaling of stain gradients with structural feature size. In this study, using a combination of atomistic and theoretical approaches, we elucidate the “effective” sizedependent piezoelectric and elastic behavior of inhomogeneously strained non-piezoelectric and piezoelectric nanostructures. We argue, through computational examples, the tantalizing possibility of creating “apparently piezoelectric” nano-composites without piezoelectric constituents and the emergence of size-dependent “giant piezoelectricity” in paradigmatical nanostructures. Finally, we propose that flexoelectricity is an important and essential contributor to the intrinsic dead-layer effect in high permittivity ferroelectric based nanocapacitors.