Spin-valley coupling in defect-bound electrons in a MoS₂ transistor

Atomically thin two-dimensional transition metal dichalcogenides, such as MoS₂, are actively being explored for applications in next-generation electronics and quantum information processing. Electronic ground states in the conduction band of MoS₂ are predicted spin-valley locked, promising robust quantum bits (qubits) with potentially enhanced spin lifetime. However, the difficulty in achieving high mobility devices with transparent contact at low temperatures has made it challenging to achieve confinement of single or few-electron spins to quantum dots, and hence to probe spin-valley locked states experimentally. We report resonant tunneling through well-resolved spin states in MoS₂, whose spin-valley coupling we demonstrate by ground-state magneto-spectroscopy. We measure an effective out-of-plane g-factor as large as ≈ 8 and spin-orbit coupling of Δ_SO ∼ 100 eV. We believe that our results are a significant step towards harnessing electron spins in these materials to realize spin-valley qubits.