Description

Two-dimensional (2D) van der Waals heterostructures, composed of graphene and transition metal dichalcogenides have emerged as an exciting platform for investigating the interplay between strong electronic correlations and non-trivial band topology as illustrated by the recent observation of Wigner/Hall crystals and fractional quantum anomalous Hall insulators within moiré superlattices of rhombohedral graphene aligned with hBN), which non-abelian excitations are of major interest for decoherence-free quantum computation. Following our recent STM work on Bernal bilayer graphene, the central objective of this PhD project is to study the phase diagram of rhombohedral graphene by STM in two geometries. In the standard STM/STS geometry for studying the density of states of moiré minibands, the symmetry of moiré orbitals. In the charge sensing geometry, where a top graphene layer is stacked on the rhombohedral layer, to measure the electronic compressibility and the Chern number of minibands. This geometry will allow the exploration of the phase diagram as function of electrical field where the fractional quantum anomalous phases are observed.

Skills required

Student interested in fundamental solid-state physics. Students with a Master's degree in solid-state physics, quantum physics, or quantum devices are encouraged to apply. Students will be required to fabricate samples and carry out experiments; a strong interest in experimental physics is therefore necessary.

Bibliography

[1] Z. Lu et al., Extended quantum anomalous Hall states in graphene/hBN moiré superlattices, Nature 637, 1090 (2025).

Related group publications:
[2] V. Sheina et al., Hydrogenic spin-valley states of the bromine donor in 2H-MoTe2, Commun. Phys. 6, 1 (2023).
[3] Y. Wang, M. Haze, H. T. Bui, W.-H. Soe, H. Aubin, A. Ardavan, A. J. Heinrich, and S.-H. Phark, Universal quantum control of an atomic spin qubit on a surface, Npj Quantum Information 9, 1 (2023).

Keywords

STM, graphene, rhombohedral, quantum anomalous Hall