Conveyor-mode electron shuttling through a T-junction in Si/SiGe

Beer M(1)(2), Xue R(1), Deda L(1), Trellenkamp S(3), Tu JS(3), Surrey P(1), Seidler I(1), Bluhm H(1)(2), Schreiber LR(4)(5). Conveyor-mode shuttling in gated Si/SiGe devices enables adiabatic transfer of single electrons, electron patterns and spin qubits confined in quantum dots across several microns with a scalable number of signal lines. To realize their full potential, linear shuttle lanes must connect into a two-dimensional grid with controllable routing. We introduce a T-junction device linking two independently driven shuttle lanes. Electron routing across the junction requires no extra control lines beyond the four channels per conveyor belt. We measure an inter-lane charge transfer fidelity of F = 100.0000000-9×10-7+0 % at an instantaneous electron velocity of 270 mm s-1. The filling of 54 quantum dots is controlled by simple atomic pulses, allowing us to swap electron patterns, laying the groundwork for a native spin-qubit SWAP gate. This T-junction establishes a path towards scalable, two-dimensional quantum computing architectures with flexible spin qubit routing for quantum error correction.