Investigation of P_CV_Si ⁻ defect in 4H–SiC as a candidate for a qubit

Abstract Exploration of spin defects in semiconductors for possible qubits encourages the development of the quantum field. Silicon carbide (SiC) is a suitable platform to carry spin defects, due to its excellent electrical, mechanical and optical properties, together with its convenience for crystallographic growth and doping processes. In this study, a negatively charged phosphorus-vacancy (P C V Si − ) defect, consisting of a silicon vacancy and nearby substitution of a phosphorus atom to a carbon atom in 4H–SiC, is investigated by first-principles calculations. This defect is demonstrated to possess a high spin ( S = 1) with relatively low formation energy. Computed zero-phonon line energy and zero-field splitting parameters of this defect are close to those of neutral divacancy (V C V Si 0 ), negatively charged nitrogen-vacancy center (N C V Si − ) and some other color centers, which indicate a similarity of both optical and spin properties among them. Moreover, the electron spin coherence time of this defect turns out to be 1.15–1.40 ms. Such a long coherence time provides the defect with reliability for quantum information processing. Our results show that the P C V Si − defect can be a promising candidate for a qubit.