Towards Probing Quantum Many-Body Phases in Bilayer Graphene Using Large Quantum Dots

The exploration of quantum many-body phases in Bernal bilayer graphene reveals a rich landscape of tunable quantum phenomena, with potential applications in advanced quantum devices.[1][2] Despite the significant interest in this area, using quantum dots to probe the quantum phases has been limited, which is essential in controlling the level of degeneracy towards the realization of qudit states. Here we present our work using a gate-defined quantum dot with a relatively large size, which gives a higher density resolution during the sequential addition of carriers.[3] The larger size of the dot also reduces the energy level spacing, enabling the investigation of phases with small energy scales. We tune the dot to the large density region where many carriers are present and quantum many-body phases form inside the dot. By applying magnetic fields, the Coulomb peak trajectories versus gate voltage enable the magnetism of the varying phases to be identified, yielding evidence for valley magnetic phases. This approach is readily adaptable to explore the properties of tunable many-body phases in other systems such as twisted bilayer graphene.



[1] Zhou, et al. Science 375.6582 (2022): 774-778.

[2] Koh, et al. arXiv:2407.09612 (2024).

[3] Banszerus, et al. Nano letters 18.8 (2018): 4785-4790.