Negative differential resistance in a flexible graphite silicone composite

The need for flexible electronic devices that are compatible with biology is driving the search for novel materials. Here we report a composite of graphite nanoparticles incorporated into a silicone rubber matrix that exhibits a robust negative differential resistance (NDR) region. Through consideration of the lamellar structure of the nanoparticles and the formation of electric field domains within the sample, we show that the NDR originates from a semimetal to insulator transition of an embedded bilayer within the graphite nanoparticle. We employ the rubber's intrinsic flexibility to demonstrate how strain induced in the composite, through an axial deformation, modifies the NDR region. A strain of ε = 17.5% shifts the onset of the NDR by 30%.