Boron-doped graphene nanoribbons are promising platforms for developing organic materials with magnetic properties. Boron dopants can be used to create localized magnetic states in nanoribbons with tunable interactions. Controlling the coherence times of these magnetic states is the very first step in designing materials for quantum computation or information storage. In this work, we address the connection between the relaxation time and the position of the dopants for a series of boron-doped graphene nanofragments. We combine Redfield theory and ab initio calculations of magnetic properties to unveil the mechanism that governs spin relaxation in solution. We demonstrate that relaxation times can be in the order of 1 ms for the selected graphene nanofragments. A detailed analysis of the relaxation mechanism reveals that the spin decoherence is fundamentally driven by fluctuations of the spin-orbit coupling, and the hyperfine interaction facilitated by the thermal motion of the graphene nanofragments. The close connection between relaxation time, hyperfine interaction and the spin-orbit coupling offers the perspective of designing attractive materials with long-lived spin states.

中文翻译：

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硼掺杂石墨烯纳米带中的电子自旋弛豫。


硼掺杂石墨烯纳米带是开发具有磁性的有机材料的有前途的平台。硼掺杂剂可用于在纳米带中产生具有可调相互作用的局部磁态。控制这些磁态的相干时间是设计用于量子计算或信息存储的材料的第一步。在这项工作中，我们解决了一系列硼掺杂石墨烯纳米碎片的弛豫时间和掺杂剂位置之间的联系。我们将 Redfield 理论和磁特性的从头开始计算相结合，揭示了控制溶液中自旋弛豫的机制。我们证明，所选石墨烯纳米片段的弛豫时间可以在 1 ms 左右。对弛豫机制的详细分析表明，自旋退相干基本上是由自旋-轨道耦合的波动以及石墨烯纳米碎片的热运动促进的超精细相互作用驱动的。弛豫时间、超精细相互作用和自旋轨道耦合之间的密切联系为设计具有长寿命自旋态的有吸引力的材料提供了前景。