标题： 电可调手性反铁磁体中的皮秒级八极涨落 显示英文标题

标题： Electrically Tunable Picosecond-scale Octupole Fluctuations in Chiral Antiferromagnets

摘要： 我们提出了一种关于纳米尺度手性反铁磁体（AFMs）与热浴和自旋注入源耦合时八极序参数弛豫时间的理论。 通过随机自旋动力学模拟，我们证明当八极涨落的势垒相对于热能降低时，八极矩通过两种不同的机制$-$克服势垒和进动去相位$-$进行弛豫。 值得注意的是，八极矩的弛豫速度比典型的偶极序参数快几个数量级，达到皮秒时间尺度。 通过将兰格理论与手性AFMs中八极动力学的有效低能描述相结合，我们推导出了弛豫时间的解析表达式。 我们发现，在手性AFMs中的弛豫与XY磁体中的偶极弛豫类似，交换场起到了偶极场的作用。 此外，通过借鉴在自旋注入下XY磁体中序参量动力学与电流偏置约瑟夫森结之间的类比，我们提出了一种新的电调控八极弛豫时间的方案。 我们的工作为开发利用八极序参数进行信息编码的下一代自旋电子器件提供了基本见解，特别是在基于八极的概率计算中。 显示英文摘要

摘要： We present a theory for the relaxation time of the octupole order parameter in nanoscale chiral antiferromagnets (AFMs) coupled to thermal baths and spin injection sources. Using stochastic spin dynamics simulations, we demonstrate that the octupole moment relaxes through two distinct mechanisms$-$escape over a barrier and precessional dephasing$-$as the barrier for octupole fluctuations is lowered relative to the thermal energy. Notably, the octupole moment relaxes orders of magnitude faster than the typical dipolar order parameters, reaching picosecond timescales. By combining Langer's theory with an effective low-energy description of octupole dynamics in chiral AFMs, we derive analytical expressions for the relaxation times. We find that relaxation in chiral AFMs parallels dipole relaxation in XY magnets, with exchange fields serving the role of the dipole fields. Further, by drawing on the analogy between order parameter dynamics in XY magnets under spin injection and current-biased Josephson junctions, we propose a new scheme for electrically tuning the octupole relaxation times. Our work offers fundamental insights for the development of next-generation spintronic devices that harness octupole order parameters for information encoding, especially in octupole-based probabilistic computing.