Strain Engineering of 2-Dimensional Materials
Strain Engineering of 2D-bonded Materials to tune their electrical and quantum properties
Two-dimensional materials provide an unusual platform in which mechanical deformation can be used to control electronic, optical, structural, and quantum behavior. My group has investigated the fundamental mechanics that govern strain transfer in these materials, with particular emphasis on how strain propagates across interfaces and between individual atomic layers. Because interfacial adhesion, sliding, lattice orientation, and layer stacking can strongly affect the strain transmitted through a heterostructure, externally applied deformation does not necessarily yield a uniform or predictable material response. Understanding these mechanisms is therefore essential for translating strain engineering from individual demonstrations into reliable methods for controlling nanoscale devices.
My group developed a multiscale computational framework combining density functional theory, molecular dynamics, and finite element modeling to examine strain transfer from substrates and thin-film stressors into graphene, transition-metal dichalcogenides, and related van der Waals materials. First-principles calculations characterized interfacial adhesion, sliding barriers, and the coupling between deformation and material properties. Atomistic simulations then revealed how strain localization, interlayer slip, lattice orientation, and structural reconstruction govern the response of multilayer systems. Continuum models connected these nanoscale mechanisms to experimentally accessible thin-film and device geometries. Working closely with experimental collaborators, my group used these models to interpret strain measurements and device behavior that could not be explained through experiments alone.
This research produced several important advances. My group demonstrated how thin-film stressors can impose controlled strain in two-dimensional materials and identified directional and interfacial mechanisms that determine strain-transfer efficiency. Our work showed that applied strain can drive changes in the stacking order of trilayer graphene, including transformations between ABA and ABC configurations through interlayer sliding. We subsequently expanded this concept from uniform strain transfer to the creation and preservation of strain-induced moiré structures. In particular, we demonstrated that process-induced heterostrain can generate twist-free moiré patterns and that some reconstructed configurations can remain after the external stressor is removed, which we describe as strain memorization. These findings establish mechanical deformation and interlayer slip as tools for programming persistent stacking configurations and moiré patterns in layered materials.