Fracture and fatigue of thin crystalline SrTiO3 membranes
Varun Harbola, Ruijuan Xu, Samuel Crossley, Prastuti Singh, Harold Y. Hwang
Abstract
The increasing availability of a variety of two-dimensional materials has generated enormous growth in the field of nanoengineering and nanomechanics. Recent developments in thin film synthesis have enabled the fabrication of freestanding functional oxide membranes that can be readily incorporated in nanomechanical devices. While many oxides are extremely brittle in bulk, recent studies have shown that, in thin membrane form, they can be much more robust to fracture as compared to their bulk counterparts. Here, we investigate the ultimate tensile strength of SrTiO3 membranes by probing freestanding SrTiO3 drumheads using an atomic force microscope. We demonstrate that SrTiO3 membranes can withstand an elastic deformation with an average strain of ∼6% in the sub-20 nm thickness regime, which is more than an order of magnitude beyond the bulk limit. We also show that these membranes are highly resilient upon a high cycle fatigue test, surviving up to a billion cycles of force modulation at 85% of their fracture strain, demonstrating their high potential for use in nanomechanical applications.