Strain engineering of a pseudo gauge field superlattice in a suspended graphene nanoribbon studied by scanning probe microscopy

Engineering exotic electronic states in novel materials, which are unrealizable in traditional systems, has been the focus of intense research over the past decade. Unlike present electronics, which rely on controlling the flow of charges primarily by electric fields, strain, for example, can control electrons by generating pseudo gauge fields in 2D materials. In this talk, we report strain engineering of pseudo electric and magnetic superlattices in suspended graphene nanoribbons by extreme (>10%) strain and study the local electronic density of states by scanning tunneling microscopy. These measurements reveal Landau levels in the presence of highly non-uniform pseudo-magnetic fields. DFT and tight binding calculations imply the existence of counterpropagating snake states along the edges of the nanoribbons reminiscent of topological materials.