Transport phenomena of suspended graphene in the quantum Hall regime

Towards the goal of making qubits in graphene, it is important to develop graphene quantum point contact for quantum-gate operations. Klein tunneling effect implies that confining charge carriers in graphene using external potential is challenging. Hence, we resort to electric-field controlled band gap opening for charge confinement. We have successfully fabricated high quality suspended few-layer graphene devices with local electrostatic gates. In this talk, we present our observation of voltage-controlled band gap opening and anomalous quantum Hall features upon applying vertical electrical filed, revealing rich physics of symmetry breaking in the few-layer graphene system.