Scalable Gate Architecture for a One-Dimensional Array of Semiconductor Spin Qubits

Abstract

We demonstrate a 12-quantum-dot device fabricated on an undoped Si/SiGe heterostructure as a proof of concept for a scalable, linear gate architecture for semiconductor quantum dots. The device consists of nine quantum dots in a linear array and three single-quantum-dot charge sensors. We show reproducible single-quantum-dot charging and orbital energies, with standard deviations less than 20% relative to the mean across the nine-dot array. The single-quantum-dot charge sensors have a charge sensitivity of 8.2 x 10(-4) e/root Hz and allow for the investigation of real-time charge dynamics. As a demonstration of the versatility of this device, we use single-shot readout to measure the spin-relaxation time T-1 = 170 ms at a magnetic field B = 1 T. By reconfiguring the device, we form two capacitively coupled double quantum dots and extract a mutual charging energy of 200 mu eV, which indicates that 50-GHz two-qubit gate-operation speeds are feasible.