Quantum-Hall Spectroscopy of Elliptically Deformed Graphene Nanobubble Qubits

With recent advances in strain-engineering technology of graphene and 2D materials, graphene quantum dots (QDs) defined by the strain-induced pseudo-magnetic fields (PMFs) have been of interest, with the feasibility of tunable graphene qubits. Here, we theoretically investigate how the electronic states of the nanobubble QDs are influenced by the geometrical anisotropy of the elliptical-shape nanobubbles. We examine the energy levels of the single QD (SQD) and double QD (DQD) spectra by varying the elliptical deformation in the $x$ and $y$ axes, respectively. We found that the SQD and DQD show distinguished behavior with respect to the direction of the elliptical deformation. While the SQD levels are substantially affected by the $y$-directional deformation, the DQD levels are largely shifted by the $x$-directional deformation.