Sharp periodic Ge concentration modulations beyond the valley wavevector k₀ in nuclear-spin-free Si quantum wells 在无核自旋Si量子阱中实现超过价电谷波矢k₀的尖锐Ge周期调制 preprintSi spin qubitsMBE
academic team
arXiv:2605.31358 · 2026-05-29
Deterministic valley splitting in Si quantum wells is one of the gating problems for scalable silicon spin-qubit quantum computing — and it requires Ge concentration modulations on the order of the Si valley wavevector k₀ (≈ 9.7 nm⁻¹), which means near-monolayer growth control. This work uses ²⁸Si and ⁷²Ge molecular beam epitaxy to demonstrate Ge-modulated Si quantum wells at periods down to ~2 nm with sharp, well-defined modulations. Practically: the materials growth bottleneck on silicon spin-qubit roadmaps just moved measurably. Si量子阱中确定性的谷劈裂,是可扩展硅自旋量子比特计算的瓶颈问题之一——其要求Ge浓度调制达到Si价电谷波矢k₀(约9.7 nm⁻¹)量级,即需要近单层级的生长控制。本工作以²⁸Si和⁷²Ge分子束外延,演示了周期可低至约2 nm、调制界面清晰的Ge调制Si量子阱。实质意义:硅自旋量子比特路线图上的材料生长瓶颈,发生了可量化的位移。