Impact of the local valley splitting on the coherence of conveyor-belt spin shuttling in $^{28}$Si/SiGe
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866915855516827648 |
|---|---|
| author | Volmer, Mats Struck, Tom Tu, Jhih-Sian Trellenkamp, Stefan Esposti, Davide Degli Scappucci, Giordano Cywiński, Łukasz Bluhm, Hendrik Schreiber, Lars R. |
| author_facet | Volmer, Mats Struck, Tom Tu, Jhih-Sian Trellenkamp, Stefan Esposti, Davide Degli Scappucci, Giordano Cywiński, Łukasz Bluhm, Hendrik Schreiber, Lars R. |
| contents | Silicon quantum chips offer a promising path toward scalable, fault-tolerant quantum computing, with the potential to host millions of qubits. However, scaling up dense quantum-dot arrays and enabling qubit interconnections through shuttling are hindered by uncontrolled lateral variations of the valley splitting energy $E_{VS}$. We map $E_{VS}$ across a $40 \, $nm x $400 \, $nm region of a $^{28}$Si/Si$_{0.7}$Ge$_{0.3}$ shuttle device and analyze the spin coherence of a single electron spin transported by conveyor-belt shuttling. We observe that the $E_{VS}$ varies over a wide range from $1.5 \, μ$eV to $200 \, μ$eV and is dominated by SiGe alloy disorder. In regions of low $E_{VS}$ and at spin-valley resonances, spin coherence is reduced and its dependence on shuttle velocity matches predictions. Rapid and frequent traversal of low-$E_{VS}$ regions induces a regime of enhanced spin coherence explained by motional narrowing. By selecting shuttle trajectories that avoid problematic areas on the $E_{VS}$ map, we achieve transport over tens of microns with coherence limited only by the coupling to a static electron spin entangled with the mobile qubit. Our results provide experimental confirmation of the theory of spin-decoherence of mobile electron spin-qubits and present practical strategies to integrate conveyor-mode qubit shuttling into silicon quantum chips. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_03773 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Impact of the local valley splitting on the coherence of conveyor-belt spin shuttling in $^{28}$Si/SiGe Volmer, Mats Struck, Tom Tu, Jhih-Sian Trellenkamp, Stefan Esposti, Davide Degli Scappucci, Giordano Cywiński, Łukasz Bluhm, Hendrik Schreiber, Lars R. Quantum Physics Silicon quantum chips offer a promising path toward scalable, fault-tolerant quantum computing, with the potential to host millions of qubits. However, scaling up dense quantum-dot arrays and enabling qubit interconnections through shuttling are hindered by uncontrolled lateral variations of the valley splitting energy $E_{VS}$. We map $E_{VS}$ across a $40 \, $nm x $400 \, $nm region of a $^{28}$Si/Si$_{0.7}$Ge$_{0.3}$ shuttle device and analyze the spin coherence of a single electron spin transported by conveyor-belt shuttling. We observe that the $E_{VS}$ varies over a wide range from $1.5 \, μ$eV to $200 \, μ$eV and is dominated by SiGe alloy disorder. In regions of low $E_{VS}$ and at spin-valley resonances, spin coherence is reduced and its dependence on shuttle velocity matches predictions. Rapid and frequent traversal of low-$E_{VS}$ regions induces a regime of enhanced spin coherence explained by motional narrowing. By selecting shuttle trajectories that avoid problematic areas on the $E_{VS}$ map, we achieve transport over tens of microns with coherence limited only by the coupling to a static electron spin entangled with the mobile qubit. Our results provide experimental confirmation of the theory of spin-decoherence of mobile electron spin-qubits and present practical strategies to integrate conveyor-mode qubit shuttling into silicon quantum chips. |
| title | Impact of the local valley splitting on the coherence of conveyor-belt spin shuttling in $^{28}$Si/SiGe |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2510.03773 |