Oxide-based solid-state spin qubit

Optically accessible solid-state spin centers are promising platforms for quantum information technology. We present an algebraic relationship between electron spin coherence time (T2) and various parameters, including g-factor and spin densities, through cluster correlation expansion (CCE) calculations. This led to a predictive formula for T2, enabling the identification of over 700 potential qubit materials with T2 exceeding 1 ms; 60% of the potential qubit materials are oxides, suggesting an unfocused materials system as a solid-state spin qubit. In addition, our experimental investigations into Ce-implanted oxide materials, specifically MgO and spinel (MgAl2O4), which are well-known in the field of spintronics as barrier materials of the high-performance magnetic tunnel junctions, have revealed promising optical properties; forsterite and spinel show polarization-dependent emission at low temperatures, suggesting the optical initialization and readout of spin state necessary for the qubit application similar to Ce3+ center in Y3Al5O12.