Flat bands by design in periodically gated bilayer graphene

Recent experimental and theoretical efforts in the shaping and texturing of the electron wave-function take as an example periodic arrangement of atoms in a crystal that appear in nature. For example, as observed in semiconductors, electrons acquire new properties depending on the types of atoms and their arrangement in the lattice: the spectrum becomes gapped, electrons and holes acquire effective masses, etc. In efforts to mimic this behavior and with the purpose of tuning it at will, researchers have created through various means periodic potentials for two-dimensional electron gas systems. These can be either the states formed at the interface of two semiconductors, the surface state in metals, or the naturally confined electrons in two-dimensional materials like graphene. Based on very recent experimental developments, we propose to theoretically study a sandwich-like configuration containing patterned graphene gates, imposing a periodic potential on a bilayer graphene active layer. The main goal is to artificially create and tune lattices with peculiar properties, otherwise not easily found in nature: Lieb, kagome or dice lattices that show flat electronic bands with topological properties and show great potential for novel physics. This proposal is situated in the context of a collaboration with an experimental group working on building such devices. The planned close interaction will provide input on realistic gate configurations, possibility to validate our approach, to model electric transport measurements in the presence of magnetic fields and to predict gate configurations which realize the propose flat topological bands.

Keywords:GATING, GRAPHENE-BASED LAYERS, GRAPHENE, ELECTRONIC TRANSPORT

Disciplines:Nanophysics and nanosystems, Surfaces, interfaces, 2D materials