Investigation on PCVSi- defect in 4H-SiC as a candidate of qubit

Abstract Exploration of spin defects in semiconductors for possible qubits encourages the development of quantum field. Silicon carbide (SiC) is a suitable platform to carry spin defects, due to its excellent electrical, mechanical, optical properties, together with convenience to crystallographic growth and doping processes. As for this study, a negatively charged phosphorus-vacancy (PCVSi-) defect, consisting of silicon vacancy and nearby substitution of phosphorus atom to carbon atom in 4H-SiC, was investigated by first-principles calculations. This defect was demonstrated to possess a high spin (S = 1) with relatively low formation energy. Computed zero phonon line (ZPL) energy and zero-field splitting (ZFS) parameters of this defect were close to those of neutral divacancy (VCVSi0) and some other color centers, which indicated a similarity of both optical and spin properties among them. Moreover, electron spin coherence time of this defect turned out to be 1.15 - 1.40 ms. Such long coherence time provided the defect with availability for quantum applications. Our results show that PCVSi- defect can be a promising candidate of qubit.