Quantum Dots in Bilayer Graphene

Graphene and bilayer graphene are promising materials for quantum technologies. Considerable effort has been devoted to the study of quantum dot (QD) devices based on these materials, with the aim of benchmarking spin qubits in such carbon materials. The main challenge in using graphene to fabricate QDs is the lack of a band gap, which prevents electrostatic confinement of carriers. However, this is possible in bilayer graphene (BLG) thanks to its electric field tunable band gap (up to more than 100 meV), which allows true electrostatic confinement. This talk will present the state of the art of gate-controlled single and double quantum dots in electrostatically gapped BLG. The QD devices show a high degree of control, enabling gate-defined electron-hole and electron-electron double quantum dots with single electron and hole occupancy. The unique band structure properties of BLG provide magnetic field tunability of the valley degree of freedom, allowing the study of spin-orbit coupling and the observation of a particle-hole symmetry protected spin-valley blockade, potentially useful as a read-out mechanism for single-particle spin qubits.