Fracture and Fatigue of Thin Crystalline SrTiO$_3$ Membranes

TL;DR

This study investigates the fracture and fatigue properties of ultra-thin SrTiO3 membranes, revealing their high strength and resilience, which surpass bulk material limits and demonstrate potential for nanomechanical device applications.

Contribution

It provides the first detailed analysis of the tensile strength and fatigue life of freestanding SrTiO3 membranes at nanoscales, highlighting their robustness compared to bulk oxide materials.

Findings

SrTiO3 membranes withstand ~6% strain before fracture

Membranes survive up to a billion fatigue cycles at 85% of fracture strain

Thin membranes are significantly more resilient than bulk SrTiO3

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 SrTiO$_3$ membranes by probing freestanding SrTiO$_3$ drumheads using an atomic force microscope. We demonstrate that SrTiO$_3$ 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.