Non-Uniform Strain Engineering of 2D Materials

2D materials are elastic substances that can sustain high strain. While the response of these materials to spatially uniform strain is well studied, the effects of spatially non-uniform strain are understood much less. In this review, we examine the response of two different 2D materials, transition metal dichalcogenides and graphene, under non-uniform strain. First, we analyze pseudo-magnetic fields formed in graphene subjected to highly localized non-uniform strain. Second, we discuss the effect of non-uniform strain on excitons in non-uniformly strained TMDC. We show that while transport or “funneling” of excitons is relatively inefficient, a different process, a strain-related conversion of excitons to trions is dominant. Finally, we discuss the effects of uniform and non-uniform strain in a graphene-based phononic crystal. We find that uniform strain can be used to broadly tune the frequency of the phononic bandgap by more than 350 % and non-uniform strain smears that bandgap.