Rapid high-fidelity spin state readout in Si/SiGe quantum dots via radio-frequency reflectometry*

Radio-frequency (rf) reflectometry, while enabling rapid high-fidelity readout of GaAs spin qubits, is challenging to implement in accumulation-mode Si quantum dot devices. The difficulty arises when a large parasitic gate capacitance is distributed along a relatively large resistance two-dimensional electron gas (2DEG). Here we will present minor design changes that when implemented in a Si/SiGe quantum dot device enable charge readout fidelity above 99.9% in 300ns using rf reflectometry. The rf compatible Si design can perform single-shot readout of spin states via spin-selective tunneling in microsecond integration times. We will also show high fidelity singlet and triplet readout of a double quantum dot via Pauli spin blockade. With the use of a charge latching mechanism we achieve a maximum fidelity of 99.0%.