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تسجيل مستخدم جديدQuantum decoherence dynamics of divacancy spins in silicon carbide
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Long coherence times are key to the performance of quantum bits (qubits). Here, we experimentally and theoretically show that the Hahn-echo coherence time (T2) of electron spins associated with divacancy defects in 4H-SiC reaches 1.3 ms, one of the longest T2 times of an electron spin in a naturally isotopic crystal. Using a first-principles microscopic quantum-bath model, we find that two factors determine the unusually robust coherence. First, in the presence of moderate magnetic fields (300 G and above), the 29Si and 13C paramagnetic nuclear spin baths are decoupled. In addition, because SiC is a binary crystal, homo-nuclear spin pairs are both diluted and forbidden from forming strongly coupled, nearest-neighbor spin pairs. Longer neighbor distances result in fewer nuclear spin flip-flops, a less fluctuating intra-crystalline magnetic environment, and thus a longer T2 time. Our results point to polyatomic crystals as promising hosts for coherent qubits in the solid state.
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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 $^{29}rm{Si}$ ($p_{rm{Si}}=4.7%$) is about 4 times larger than that of $^{13}{rm C}$ (
$p_{rm{C}}=1.1%$), the electron spin coherence time of defect centers in SiC nuclear spin bath in strong magnetic field ($B>300~rm{Gauss}$) is longer than that of nitrogen-vacancy (NV) centers in $^{13}{rm C}$ nuclear spin bath in diamond. The 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.
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Spins in solids are cornerstone elements of quantum spintronics. Leading contenders such as defects in diamond, or individual phosphorous dopants in silicon have shown spectacular progress but either miss established nanotechnology or an efficient sp
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Spin defects in silicon carbide (SiC) have attracted increasing interests due to their excellent optical and spin properties, which are useful in quantum information processing. In this work, we systematically investigate the temperature dependence o
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