Effective Hamiltonian theory for nonreciprocal light propagation in magnetic Rashba conductor
Effective Hamiltonian theory for nonreciprocal light propagation in magnetic Rashba conductor
复制标题
磁性 Rashba 导体中非互易光传播的有效哈密顿理论
DOI：
10.1103/physrevb.94.235148
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发表时间：
2016
影响因子：
3.7
通讯作者：
G. Tatara
中科院分区：
文献类型：
--
作者：
H. Kawaguchi;G. Tatara
Rashba自旋轨道相互作用通过诱导电自由度和磁自由度的混合而导致许多电磁互相关效应。在这项研究中，我们通过推导基于虚时间路径积分形式的有效哈密顿量来研究磁性Rashba导体的光学性质。我们证明有效哈密顿量可以用环面矩和四极矩来描述，正如在绝缘体多铁性的情况下所争论的那样。结果表明，环面力矩与Rashba场引起的自旋规范场一致。它通过诱导本征自旋电流引起多普勒频移，导致与极化无关的各向异性光传播（定向二色性）。另一方面，四极矩导致磁光现象，如圆极化波的法拉第效应。
Rashba spin-orbit interaction leads to a number of electromagnetic cross-correlation effects by inducing a mixing of electric and magnetic degrees of freedom. In this study, we investigate the optical properties of a magnetic Rashba conductor by deriving an effective Hamiltonian based on an imaginary-time path-integral formalism. We show that the effective Hamiltonian can be described in terms of toroidal and quadrupole moments, as has been argued in the case of insulator multiferroics. The toroidal moment turns out to coincide with the spin gauge field induced by the Rashba field. It causes Doppler shift by inducing intrinsic spin current, resulting in anisotropic light propagation (directional dichroism) irrespective of the polarization. The quadrupole moment on the other hand results in a magneto-optical phenomenon such as a Faraday effect for circularly-polarized waves.