Strain tunable transport in topological semimetal WTe₂ nanodevices

Strain is one of the most powerful external perturbations that can controllably manipulate and engineer physical properties of nanostructured quantum materials. Many previous strain engineering experiments have been performed on nanomaterials only at room temperature or only at fixed strain values that are pre-determined by some lattice mismatch. In this talk, we introduce a home-built apparatus that allows the application of elastic strain continuously and reversibly to nanostructures and nanodevices at low temperatures. Using this apparatus, we have studied the effects of uniaxial tensile strain on the transport properties of topological semimetal WTe₂ nanodevices. We discuss how the magnetoresistance and Hall resistance of WTe₂ change as a function of the uniaxial strain along different axes and at different temperatures. In combination with first principles calculations, we explain the observed anisotropic strain effects and the differing strain dependences of electron and hole concentrations in the material.