One-way transport in laser-illuminated bilayer graphene: A Floquet isolator

We explore the Floquet band structure and electronic transport in laser-illuminated bilayer graphene ribbons. By using a bias voltage perpendicular to the graphene bilayer we show how to get one-way charge and valley transport among two unbiased leads. In contrast to quantum pumping, our proposal uses a different mechanism based on generating a nonreciprocal band structure with a built-in directionality. The Floquet states at one edge of a graphene layer become hybridized with the continuum on the other layer, so the resulting band structure allows for one-way transport as in an isolator. Our proof of concept may serve as a building block for devices exploiting one-way states.