Spin-dependent Photodynamics of Silicon Vacancies in Silicon Carbide

Abstract

Silicon carbide (SiC) hosts many types of point defects whose spins can be used as a spin qubit. The negatively charged silicon-vacancy (V_Si^-) is one of them. V_Si^- in SiC has a long spin coherence time at both the room and low temperature. Besides, like the NV center in diamond, its ground spin state can be optically initialized through the spin-dependent intersystem crossing (ISC). Optically Detected Magnetic Resonance (ODMR) techniques are mainly used to measure these characteristics, and PL intensity measured by ODMR depends on the spin states. For quantum applications at room temperature, it is necessary to understand the spin properties of V_Si^- ensembleTherefore, understanding the spin-dependent photodynamics is important to figure out the spin properties of V_Si^- ensemble in SiC. In this study, The spin dynamics of the V_Si^- ensemble was demonstrated in the low magnetic field region. additionally, we also tried revealing the influence of charge state conversion in V_Si^- ensemble through the pulsed ODMR. From the experimental results, it was seen that the charge state conversion in the V_Si^- ensemble affects the photoluminescence mechanism. Then, we established the charge state conversion model in which the charge state conversion pointed out the strong cause of various issues in the V_Si^- ensemble. Through this study, we provide a better understanding for implementing quantum devices such as sensing and quantum memory using V_Si^- ensemble.