A strain-engineered graphene qubit in a nanobubble

Abstract

We propose a controllable qubit in a graphene nanobubble with emergent two-level systems induced by pseudo-magnetic fields. We found that double quantum dots can be created by the strain-induced pseudo-magnetic fields of a nanobubble, and also that their quantum states can be manipulated by either local gate potentials or the pseudo-magnetic fields. Graphene qubits clearly exhibit avoided crossing behavior as electrical detuning, with energy splittings of about few meV. We show a remarkable tunability of our device design that allows a fine control of the Landau--Zener transition probability by strain engineering of the nanobubble, showing half-and-half splitting at the avoided crossing point. Further, we demonstrate that the two-level systems in the nanobubble exhibit Rabi oscillations near the avoided crossing point, resulting in very fast Rabi cycles of a few ps.

Mechanical Properties of Small Quasi-Square Graphene Nanoflakes

“…In this case, straintronics has been considered in recent years as a way to fine-tune, among other properties, its band gap in order to use it in many different applications [10][11][12][13][14][15][16][17][18][19]. In fact, strained graphene nanobubbles have been recently proposed as qubits for quantum computing [20]. It is also possible to take advantage of the changes in properties caused by strain in sensing devices [21].…”

Electric Field Effects on Curved Graphene Quantum Dots

“…Intrinsic ripples are known to disturb the otherwise free electron paths [27], and local deformations, known as nanobubbles, can be easily produced in the material, allowing for a localised tuning of electric conductivity and more exotic phenomena, like pseudo-magnetic field generation [59,60]. It has been recently shown that double quantum dots can be created by these pseudo-magnetic fields in nanobubbles and that their quantum states can be manipulated to create a controllable qubit [61].…”