# Researchers route single electrons through a Si/SiGe T-junction with 100% transfer fidelity

- Published: 2026-11-06 15:29 UTC
- Section: Digital & Computing › Quantum technology
- Tags: conveyor mode shuttling, Si SiGe heterostructure, quantum dot array, T junction charge transfer, spin qubit routing
- URL: https://realtech.media/news/rt-895c89f0b80101c2ff84f00c_researchers_route_single/

**A 54-quantum-dot junction connects two conveyor lanes, demonstrating 2D electron pattern routing for spin qubits.**

![Researchers route single electrons through a Si/SiGe T-junction with 100% transfer fidelity](https://sgzwpqqelzmajkcubgkl.supabase.co/storage/v1/object/public/rt-media/2026/11/d2e6e5f5ae1ca233.png)
*Nature Communications*

Physicists have demonstrated conveyor-mode routing of single electrons through a two-dimensional T-junction fabricated in a Si/SiGe heterostructure, according to a study published in Nature Communications [1]. The architecture connects two orthogonal one-dimensional conveyor shuttle lanes across an active footprint of 10 μm × 5 μm [1]. Operating at an instantaneous electron velocity of 270 mm s−1, the experimental prototype achieved an inter-lane charge transfer fidelity of 100.0000000% (+0%, −9 × 10−7%) [1].

## Junction architecture and electrostatic control

The T-junction device links two independent conveyor-belt lanes, designated as the x-shuttle and y-shuttle, joined at a 90° angle [1]. The structure contains 54 quantum dots in total, with single-electron transistors placed at the exterior-facing ends of the lanes to perform charge readout [1]. To overcome wiring bottlenecks without scaling up control lines, the electrostatic gates are grouped into coordinated sets driven by four channels per conveyor belt [1]. Overall operation and routing across the entire 54-dot system are managed using eleven voltage channels that deliver eight basic atomic pulse sequences [1]. 

## Charge transfer and electron pattern permutations

During routing, static gate bias was set to 330 mV for the active sets, while termination gates defining the lane ends were held at 0 V to create sharp potential boundaries [1]. The atomic pulses govern charge loading, shuttling, and inter-lane transfers without introducing supplementary gate terminals at the junction point [1]. Beyond transporting single electrons between orthogonal axes, researchers demonstrated the manipulation and permutation of filled quantum dots across the array [1]. These verified pattern swaps establish the baseline operation required for native spin-qubit SWAP gates in two-dimensional spin quantum computing architectures [1].

## Sources

1. [Nature Communications](https://doi.org/10.1038/s41467-026-78805-1)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-895c89f0b80101c2ff84f00c_researchers_route_single/