Reversible Straining of van der Waals Nanoribbons

Applying lattice strain is a proven method for controlling correlated and topological phases in crystalline materials. While numerous techniques have been developed to strain bulk crystals, methods for manipulating exfoliated van der Waals (vdW) materials are relatively underdeveloped; contemporary approaches leverage differential thermal contraction between the target material and encapsulating layers, nanoscale manipulation with an atomic force microscope (AFM), and, most recently, electrostatically-tunable uniaxial strain cells. Here, we present a complimentary, and potentially more facile, approach to deterministically apply strain to exfoliated vdW materials using microstructured polymer stamps or commercial AFM cantilevers mounted to glass slides. As a representative platform, we demonstrate compressive and tensile strain reaching |ϵ| = 1.5% with exfoliated nanoribbons of a quasi-one-dimensional (quasi-1D) vdW material on hexagonal boron nitride (hBN). Using numerous, orthogonal structural characterization methods we confirm the strain is elastic and, due to the low friction at vdW interfaces, even reversible. Moreover, we are able to manipulate fully encapsulated nanoribbons, suggesting this method can be employed to strain air-sensitive materials. We conclude by discussing how this method could pave the way for complex strain configurations and dynamic devices.