螺旋度选择性反铁磁共振的非厄米控制

中文摘要 AI 辅助

我们研究了具有亚晶格依赖阻尼和自旋轨道扭矩的反铁磁绝缘体/非磁性金属结中的非厄米反铁磁共振。通过将线性化的朗道-里夫希茨-吉尔伯特（LLG）方程表述为一个2x2非厄米本征值问题，我们推导出了复共振频率、例外点条件和稳定性阈值条件。我们表明，从稳定侧接近稳定性阈值可使最大吸收响应最大化。在稳定侧阈值附近，吸收光谱表现出强烈增强和线宽变窄，以及在亚太赫兹 regime 中明显的螺旋度依赖性，可通过反转自旋轨道扭矩来切换。我们还通过求解完整的LLG动力学证实，越过阈值会导致增益和自振荡。这些结果确定稳定性阈值是在亚太赫兹/太赫兹 regime 中增强吸收和实现偏振选择性的关键控制原理。

英文摘要

We study helicity-selective antiferromagnetic resonance in an antiferromagnetic-insulator/nonmagnetic-metal junction with sublattice-dependent damping and spin-orbit torque. By formulating the linearized Landau--Lifshitz--Gilbert equation as a 2x2 non-Hermitian eigenvalue problem, we analyze the complex resonance frequencies and the stability threshold, using MnF$_2$ parameters as a representative example of a uniaxial antiferromagnet. We show that the absorption is strongly enhanced near the stability threshold, where one helicity mode becomes weakly damped, leading to linewidth narrowing and pronounced helicity selectivity in the sub-THz regime. The selected helicity can be switched by reversing the current direction, which reverses the spin-orbit torque acting on the interfacial sublattice. These results identify stability-threshold control as a design principle for electrically tunable helicity-selective antiferromagnetic resonance in uniaxial antiferromagnets.

发表机构

• Institute for Solid State Physics, University of Tokyo（东京大学固体物理研究所）
• Department of Materials Physics, Nagoya University（名古屋大学物质物理学系）
• Institute of Industrial Science, The University of Tokyo（东京大学工业科学研究所）

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