Transport Measurements using Hall Cross Geometry to probe Electronic States of Graphene Nanoribbons*

Graphene nanoribbons (GNRs) have unique electronic properties that can potentially be used to develop electron spin-based qubits.  The LaAlO3/SrTiO3 (LAO/STO) correlated nanoelectronics platform [1] enables single GNRs to be addressed both optically and electrically.  Here we use a LAO/STO-based sketched single electron transistor (SketchSET) [2] to probe the energies at which a single electron is added to a GNR.  This addition energy spectrum [3] is expected to be influenced by local electric fields from proximal sketched gates as well as global magnetic fields which can Zeeman split the energy states. The nanocross geometry has shown to probe the LAO/STO electron system and be highly reproducible [4]. A nanocross device over a GNR has the potential to measure spin polarization in a magnetic field. This information is complementary to other probes, e.g., THz spectroscopy [5] and STM which also provide detailed information about the electronic structures of these GNR-based spin qubit candidates.

[1] Cen, C., et al. Science 323, 1026–1030 (2009)

[2]  Cheng, G. et al. Nat. Nanotechnol. 6, 343–347 (2011)

[3] Tarucha, et al. Phys. Rev. Lett. 77, 3613–3616 (1996)

[4] Nethwewala, A. et al. Nanoscale Horizons 4, 1194-1201 (2019)

[5] Sheridan, E. et al. APL Materials 9, 071101 (2021)