Impact of disorder on the distribution of gate coupling strengths in a spin qubit device

TL;DR

This paper presents a simulation method to analyze how disorder affects gate coupling strengths in spin qubit devices, aiding in device design and understanding variability.

Contribution

We develop a spin-qubit device simulation that accounts for disorder, enabling prediction of coupling strength distributions and comparison with experimental data.

Findings

Simulation matches experimental coupling distributions within disorder variance

Analysis of non-planar FinFET-inspired geometry demonstrates method flexibility

Disorder significantly influences gate coupling strength variability

Abstract

A scalable spin-based quantum processor requires a suitable semiconductor heterostructure and a gate design, with multiple alternatives being investigated. Characterizing such devices experimentally is a demanding task, with the full development cycle taking at least months. While numerical simulations are more time-efficient, their predictive power is limited due to unavoidable disorder and device-to-device variation. We develop a spin-qubit device simulation for determining the distribution of the coupling strengths between the electrostatic gate potentials and the effective device Hamiltonian in presence of disorder. By comparing our simulation results with the experimental data, we demonstrate that the coupling of the gate voltages to the dot chemical potential and the interdot tunnel coupling match up to disorder-induced variance. To demonstrate the flexibility of our approach, we also analyze an alternative non-planar geometry inspired by FinFET devices.