Spin-orbital-momentum locking under odd-parity magnetic quadrupole ordering
Spin-orbital-momentum locking under odd-parity magnetic quadrupole ordering
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DOI：
10.1103/physrevb.104.045117
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发表时间：
2021-05
影响因子：
3.7
通讯作者：
S. Hayami;H. Kusunose
中科院分区：
文献类型：
--
作者：
S. Hayami;H. Kusunose
奇宇称磁和磁环极在没有空间反转和时间反转对称性的情况下是多铁性和非互易光学现象的来源。我们研究了由突现奇宇称磁四极（MQ）引起的电子态，作为磁奇宇称多极的一个代表性例子。结果表明，MQ的自发排序导致动量空间中的反对称自旋轨道极化，对应于每个波矢量处的自旋轨道动量锁定。通过对称论证，我们证明了轨道或亚格自由度是产生自旋轨道动量锁定所不可缺少的。我们证明了在三轨道系统中，电子带结构是如何被MQ顺序调制的，其中MQ是由具有不同空间对等的轨道之间的自旋相关杂化激活的。自旋轨道动量锁定与带结构中磁场诱导的对称和反对称自旋极化、电流诱导畸变和磁电效应等交叉相关现象的微观起源有关。我们还讨论了反铁磁体中类似的自旋轨道动量锁定，其中MQ自由度是通过亚晶格系统中的反铁磁自旋结构激活的。
Odd-parity magnetic and magnetic toroidal multipoles in the absence of both spatial-inversion and time-reversal symmetries are sources of multiferroic and nonreciprocal optical phenomena. We investigate electronic states caused by an emergent odd-parity magnetic quadrupole (MQ) as a representative example of magnetic odd-parity multipoles. It is shown that spontaneous ordering of the MQ leads to an antisymmetric spin-orbital polarization in momentum space, which corresponds to a spin-orbital momentum locking at each wave vector. By symmetry argument, we show that the orbital or sublattice degree of freedom is indispensable to give rise to the spin-orbital momentum locking. We demonstrate how the electronic band structures are modulated by the MQ ordering in the three-orbital system, in which the MQ is activated by the spin-dependent hybridization between the orbitals with different spatial parities. The spin-orbital momentum locking is related with the microscopic origin of cross-correlated phenomena, e.g., the magnetic-field-induced symmetric and antisymmetric spin polarization in the band structure, the current-induced distortion, and the magnetoelectric effect. We also discuss similar spin-orbital momentum locking in antiferromagnet where the MQ degree of freedom is activated through the antiferromagnetic spin structure in a sublattice system.