Modeling, Design, and Optimization of a Solid State Electron Spin Qubit

This paper describes a solid state system in which a qubit is realized as the spin of a single trapped electron in a quantum dot and read functionality is via an adjacent quantum wire with a single or a small number of conductive states. Because of the limited design window for this system, simulation is an important guide to an experimental search for successful designs. We use a semianalytic approximation that is accurate enough to provide meaningful results and computationally simple enough to allow high throughput, as needed for design and optimization. In particular, we find designs that achieve double pinchoff (i.e., a single trapped electron in the dot and a single conductive state in the wire). After relaxing the design requirements to allow for a small number of conductive states in the wire, we find successful designs that are optimally robust, in the sense that their success is unlikely to be affected by fabrication errors.