Towards an Exchange-Only Compatible Spin-Photon Interface in Si/SiGe

Coherent coupling of spin qubits to microwave photons has in recent years been demonstrated in Si/SiGe teasing the possibility of long-range two-qubit gates [1, 2]. In most demonstrations, spin-photon coupling is engineered by placement of micromagnets on top of the quantum dot gate stack creating an always-on charge-spin hybridization. Gradient magnetic fields, however, are fundamentally incompatible with exchange-only qubit operation as they induce state leakage out of the decoherence-free subsystem. An alternative approach that is compatible with exchange-only operation is to use large simultaneous exchange pulses to create a bias-dependent electric dipole moment in the “XRX” regime [3]. In this talk we discuss the integration and characterization of Single Layer Etch Defined Gate Electrode (SLEDGE) devices, which rely on vias to separate front-end from back-end interconnects, with superconducting microwave resonators using flip-chip bonding [4].

[1] F. Borjans et al. Nature 577 195-198 (2020)

[2] P.H. Collard et al. PRX 12, 021026 (2022)

[3] A. Pan et al. Quantum Sci. Technol. 5, 034005 (2020)

[4] W. Ha et al. Nano Lett. 22, 1443 (2021)