论文标题
Si和ge量子点中的孔旋转量子的异常零场分裂
Anomalous zero-field splitting for hole spin qubits in Si and Ge quantum dots
论文作者
论文摘要
最近在锗量子点中测量了零磁场的自旋三重态的异常能量分裂。这种零场的分裂可能会至关重要地改变隧道耦合量子点之间的耦合，这是最先进的基于自旋的量子处理器的基本构建块，对半导体量子计算机产生了深远的影响。我们开发了一个分析模型，该模型将零视场分裂与动量立方体的自旋轨道相互作用联系起来。这种相互作用自然出现在孔纳米结构中，在那里它们也可以通过外部电场调节，我们发现它们在硅和锗中特别大，从而在$ $ $ EV范围内进行了显着的零田裂片。我们通过对不同量子点的数值模拟来确认我们的分析理论，还包括其他可能的零场分裂来源。我们的发现适用于编码旋转矩形的各种当前架构，并对这些材料提供了更深入的了解，为下一代半导体量子处理器铺平了道路。
An anomalous energy splitting of spin triplet states at zero magnetic field has recently been measured in germanium quantum dots. This zero-field splitting could crucially alter the coupling between tunnel-coupled quantum dots, the basic building blocks of state-of-the-art spin-based quantum processors, with profound implications for semiconducting quantum computers. We develop an analytical model linking the zero-field splitting to spin-orbit interactions that are cubic in momentum. Such interactions naturally emerge in hole nanostructures, where they can also be tuned by external electric fields, and we find them to be particularly large in silicon and germanium, resulting in a significant zero-field splitting in the $μ$eV range. We confirm our analytical theory by numerical simulations of different quantum dots, also including other possible sources of zero-field splitting. Our findings are applicable to a broad range of current architectures encoding spin qubits and provide a deeper understanding of these materials, paving the way towards the next generation of semiconducting quantum processors.
