Nanomechanics

Linear elasticity

Materials science

Displacement (psychology)

Graphene

Nanoindentation

Thermodynamics

Physics

Finite element method

Atomic force microscopy

Nanotechnology

Psychology

Graphite

Elasticity (physics)

Psychotherapist

Condensed matter physics

Elastic modulus

Composite material

Monolayer

Nanoscopic scale

Modulus

Stiffness

Science

We measured the elastic properties and intrinsic breaking strength of free-standing monolayer graphene membranes by nanoindentation in an atomic force microscope. The force-displacement behavior is interpreted within a framework of nonlinear elastic stress-strain response, and yields second- and third-order elastic stiffnesses of 340 newtons per meter (N m(-1)) and -690 Nm(-1), respectively. The breaking strength is 42 N m(-1) and represents the intrinsic strength of a defect-free sheet. These quantities correspond to a Young's modulus of E = 1.0 terapascals, third-order elastic stiffness of D = -2.0 terapascals, and intrinsic strength of sigma(int) = 130 gigapascals for bulk graphite. These experiments establish graphene as the strongest material ever measured, and show that atomically perfect nanoscale materials can be mechanically tested to deformations well beyond the linear regime.

Measurement of the Elastic Properties and Intrinsic Strength of Monolayer Graphene