Electron spin decoherence in silicon carbide nuclear spin bath

In this paper, we study the electron spin decoherence of single defects in silicon carbide (SiC) nuclear spin bath. We find that, although the natural abundance of 29Si (~4.7%) is about 4 times larger than that of 13C (~1.1%), the electron spin coherence time of defect centers in SiC nuclear spin bath in strong magnetic field (B>300 Gauss) is longer than that of nitrogen-vacancy (NV) centers in 13C nuclear spin bath in diamond. In addition to the smaller gyromagnetic ratio of 29Si, and the larger bond length in SiC lattice, a crucial reason for this counter-intuitive result, is the suppression of heteronuclear-spin flip-flop process in finite magnetic field. Our results show that electron spin of defect centers in SiC are excellent candidates for solid state spin qubit in quantum information processing.