Crafting zero-bias one-way transport of charge and spin

摘要: We explore the electronic structure and transport properties of a metal on top (weakly coupled) two-dimensional topological insulator. Unlike widely studied junctions between nontrivial materials, systems here allow for unique band steering. First, states insulator layer may coexist with gapless bulk and, second, edge one can be selectively switched off, thereby leading to nearly perfect directional charge spin even in zero bias limit. illustrate these phenomena Bernal stacked bilayer graphene Haldane or intrinsic spin-orbit terms perpendicular voltage. This opens path realizing directed materials such as van der Waals heterostructures, monolayer, ultrathin insulators.