Ab initio simulation of spin-charge qubits based on bilayer graphene-WSe2 quantum dots.

Abstract

We propose a spin-charge qubit based on a bilayer graphene and WSe₂ van der Waals heterostructure that together form a quantum dot and demonstrate its functionality from first-principles simulations. Electron and hole confinement as well as electrically controllable spin-orbit coupling (SOC) are modeled by self-consistently solving the Schrödinger and Poisson equations with material parameters extracted from density functional theory as inputs. In both electron and hole quantum dots, we find a two orders of magnitude enhancement of SOC (1.8 meV) compared to intrinsic graphene, in the layer directly adjacent to WSe₂. Time-dependent investigations of the quantum device reveal rapid qubit gate operation in the order of picoseconds. Our simulations indicate that bilayer graphene and WSe₂ heterostructures provide a promising platform for the processing of quantum information.