AI 中文总结
研究埋入式硅量子阱中单电子自旋量子比特能量尺度，通过测量四个量子点阵列相关数据，发现静电限制可增强谷分裂，为低无序异质结构中实现特定架构建立可行途径。
AI 中文摘要
控制量子系统的能量尺度对于定义稳健的量子比特至关重要。在硅自旋量子比特中，近乎简并的导带谷从单自旋计算基态形成一个泄漏通道，这对扩展和基于穿梭的架构构成挑战。在此，我们测量了为低无序和高谷分裂共同设计的埋入式硅量子阱中单电子自旋量子比特的相关能量尺度。在平均轨道能量为2.4(2) meV的四个量子点的线性阵列中，我们报告了平均单电子谷分裂为0.40(6) meV，平均双电子单重态 - 三重态分裂为0.24(7) meV。在三个量子点中，我们观察到谷分裂与轨道能量之间有很强的相关性，平均线性系数约为0.22（meV/meV），表明静电限制可将谷分裂增加数百微电子伏特。相比之下，剩余的量子点表现出最高的谷分裂0.76(2) meV和低相关性，表明其具有出色的自旋量子比特操作特性。我们的发现表明，在埋入式量子阱中可以利用强限制有效地增强谷分裂，从而为在低无序异质结构中实现基于穿梭和稀疏占据的架构建立了一条可行的途径。
英文摘要
Controlling the energy scales of a quantum system is essential for defining robust qubits. In silicon spin qubits, the nearly degenerate conduction-band valleys create a leakage channel from the single-spin computational basis, posing a challenge to scaling and to shuttling-based architectures. Here, we measure the relevant energy scales of single-electron spin qubits in buried silicon quantum wells co-designed for low disorder and high valley splitting. Across a linear array of four quantum dots with an average orbital energy of 2.4(2) meV, we report an average single-electron valley splitting of 0.40(6) meV and an average two-electron singlet-triplet splitting of 0.24(7) meV. In three dots, we observe a strong correlation between valley splitting and orbital energy, with an average linear coefficient of $\approx 0.22$ (meV/meV), demonstrating that electrostatic confinement can increase the valley splitting by several hundred microelectronvolts. In contrast, the remaining dot exhibits the highest valley splitting of 0.76(2) meV and low correlation, suggesting excellent characteristics for spin-qubit operation. Our findings demonstrate that strong confinement can be exploited in buried quantum wells to effectively enhance the valley splitting, thereby establishing a viable path toward the realization of shuttling and sparse-occupation-based architectures in low-disorder heterostructures.
Comments10 pages, 4 figures
