Center for Spintronics and Quantum Computation, University of California, Santa Barbara, Santa Barbara, California 93106, USA.
Nat Commun. 2013;4:1819. doi: 10.1038/ncomms2854.
Crystal defects can confine isolated electronic spins and are promising candidates for solid-state quantum information. Alongside research focusing on nitrogen-vacancy centres in diamond, an alternative strategy seeks to identify new spin systems with an expanded set of technological capabilities, a materials-driven approach that could ultimately lead to 'designer' spins with tailored properties. Here we show that the 4H, 6H and 3C polytypes of SiC all host coherent and optically addressable defect spin states, including states in all three with room-temperature quantum coherence. The prevalence of this spin coherence shows that crystal polymorphism can be a degree of freedom for engineering spin qubits. Long spin coherence times allow us to use double electron-electron resonance to measure magnetic dipole interactions between spin ensembles in inequivalent lattice sites of the same crystal. Together with the distinct optical and spin transition energies of such inequivalent states, these interactions provide a route to dipole-coupled networks of separately addressable spins.
晶体缺陷可以限制孤立的电子自旋，是固态量子信息的有前途的候选者。除了专注于钻石中氮空位中心的研究外，另一种策略是寻求识别具有扩展技术功能的新自旋系统，这是一种基于材料的方法，最终可能会导致具有定制特性的“设计”自旋。在这里，我们表明，4H、6H 和 3C 多型碳化硅都具有相干且可光学寻址的缺陷自旋态，包括所有三种具有室温量子相干性的状态。这种自旋相干性的普遍性表明，晶体多态性可以成为工程化自旋量子位的自由度。长自旋相干时间允许我们使用双电子-电子共振来测量同一晶体中不同晶格位置的自旋体之间的磁偶极相互作用。加上这些不等价状态的独特光学和自旋跃迁能量，这些相互作用为单独寻址的自旋的偶极耦合网络提供了一种途径。
