Charge stabilities and spin-based quantum bit (qubit) operations in Si double quantum dot (DQD) systems, whose confinement potentials are controlled with multiple gate electrodes, are theoretically studied with a multi-scale modeling approach that combines electronic structure simulations and a Thomas-Fermi method. Taking Si$/$SiGe heterostructures as the target of modeling, this work presents in-depth discussion on designs of electron reservoirs, electrostatic controls of quantum dot (QD) shapes and corresponding charge confinement, and spin qubit manipulations. Effects of unintentional inaccuracy in DC control biases and geometric symmetries on the Rabi cycle of spin qubits are investigated to examine the robustness of logic operations. Solid connections to the latest experimental result are also established to validate the simulation method. As a rare modeling study that explores a full-stack functionality of Si DQD structures as quantum logic gate devices, this work delivers the knowledge of engineering details that are not uncovered by the latest experimental work, and can serve as a basic but practical guideline for potential device designs.

理论上通过结合电子结构模拟和Thomas的多尺度建模方法研究了Si双量子点（DQD）系统中的电荷稳定性和基于自旋的量子位（qubit）操作，该系统的约束电位由多个栅电极控制。 -费米方法。以Si$/$SiGe异质结构作为建模的目标，这项工作深入讨论了电子储层的设计，量子点（QD）形状的静电控制和相应的电荷限制以及自旋量子位操纵。研究了直流控制偏置中的意外误差和几何对称性对自旋量子位的Rabi循环的影响，以检验逻辑运算的鲁棒性。还建立了与最新实验结果的牢固连接，以验证模拟方法。作为一项罕见的建模研究，它探索了作为量子逻辑门器件的Si DQD结构的全栈功能，这项工作提供了最新实验工作中未发现的工程细节知识，并且可以作为基本但实用的指南潜在的设备设计。