Giant strain gradient elasticity in SrTiO3 membranes: bending versus stretching

Abstract

Young's modulus determines the mechanical loads required to elastically stretch a material, and also, the loads required to bend it, given that bending stretches one surface while compressing the opposite one. Flexoelectric materials have the additional property of becoming electrically polarized when bent. While numerous studies have characterized this flexoelectric coupling, its impact on the mechanical response, due to the energy cost of polarization upon bending, is largely unexplored. This intriguing contribution of strain gradient elasticity is expected to become visible at small length scales where strain gradients are geometrically enhanced, especially in high permittivity insulators. Here we present nano-mechanical measurements of freely suspended SrTiO3 membrane drumheads. We observe a striking non-monotonic thickness dependence of Young's modulus upon small deflections. Furthermore, the modulus inferred from a predominantly bending deformation is three times larger than that of a predominantly stretching deformation for membranes thinner than 20 nm. In this regime we extract a giant strain gradient elastic coupling of ~2.2e-6 N, which could be used in new operational regimes of nano-electro-mechanics.

References in corpus (4)

• Elastic properties of freely suspended MoS2 nanosheets
• Strain gradient induced polarization in SrTiO3 single crystals
• Enhanced flexoelectricity at reduced dimensions revealed by mechanically tunable quantum tunnelling
• Origin of Ferroelastic Domains in Free-Standing Single Crystal Ferroelectric Films

Cited by in corpus (11)

• Flexoelectric control of a ferromagnetic metal
• Perspective: strain and strain gradient engineering in membranes of quantum materials
• Fracture and Fatigue of Thin Crystalline SrTiO${}_3$ Membranes
• Highly confined phonon polaritons in monolayers of oxide perovskites
• Self-sealing complex oxide resonators
• Delamination-assisted ultrafast wrinkle formation in a freestanding film
• Lamellar fluctuations melt ferroelectricity
• Cold Seeded Epitaxy and Flexomagnetism in Smooth GdAuGe Membranes Exfoliated from graphene/Ge(111)
• Strain, Young's modulus, and structural transition of EuTiO3 thin films probed by micro-mechanical methods
• Integration of High-Tc Superconductors with High Q Factor Oxide Mechanical Resonators
• Reconfigurable Strain Gradient Polarity in Crystalline Oxide Nanomembranes for Controlled Bending of Functional Materials