Defect Structures and Patterns in Ultrathin Layers

Explore the modeling of out-of-plane deformation in two-dimensional sheets and bilayers, focusing on graphene and hexagonal boron nitride (hBN) in this 39-minute lecture by Professor Ken Elder from Oakland University, USA. Discover how the proposed model analytically reduces to standard models of flexible sheets in the small deformation limit. Examine applications to strained sheets, dislocation dipoles, and grain boundaries used to validate the behavior of a single flexible graphene layer. Learn about parameters obtained to match existing theoretical density functional theory calculations on layer spacing and stacking energies for graphene/graphene, hBN/hBN, and graphene/hBN bilayers. Delve into simulations of graphene/hBN twisted bilayers, revealing the structure, energy, and elastic properties of Moire patterns, and observe the crossover from well-defined hexagonal networks to smeared-out patterns as misorientation angles increase. Understand how this transition coincides with peaks in average von Mises and volumetric stresses of the bilayer.