Quantum-Hall Spectroscopy of Elliptically Deformed Graphene Nanobubble Qubits

TL;DR

This paper theoretically studies how the shape anisotropy of strain-induced graphene nanobubbles affects their electronic states, revealing directional dependencies in energy level shifts for quantum dots and double quantum dots.

Contribution

It provides a detailed analysis of the influence of elliptical deformation on the electronic spectra of graphene nanobubble quantum dots, highlighting directional effects.

Findings

Single QD energy levels are affected mainly by y-direction deformation.

Double QD energy levels are influenced predominantly by x-direction deformation.

Elliptical shape anisotropy causes distinct spectral shifts in graphene nanobubbles.

Abstract

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.