Ciclo de Seminários “Mulheres na Física” 12/03: Graphene systems under strain: controlling transport properties

Although works on mechanically deformed graphene predict the existence of valley-polarized states, optimal conditions for their detection remain challenging.  An appropriate design of the system is fundamental for controlling valley polarized currents, focusing on quantum computation applications. Here we show that in the quantum Hall regime, edge-like states in strained regions can be isolated in energy within Landau gaps. We identify precise conditions for new conducting edges-like states to be valley polarized. By appropriate design of strain profiles these states can be positioned at chosen locations in the sample. A map of local density of states as a function of energy and position reveals a unique braid pattern that serves as a fingerprint to identify valley polarization. We also present a recent study of a 4-terminal graphene device in which the mixing between the electronic confinement effects due to a magnetic field and strain results in a selective drive of the current components in the quantum Hall regime.