Conversion between electron spin and microscopic atomic rotation
Conversion between electron spin and microscopic atomic rotation
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DOI：
10.1103/physrevresearch.2.023275
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发表时间：
2020-06-03
影响因子：
4.2
通讯作者：
Murakami, Shuichi
中科院分区：
文献类型：
--
作者：
Hamada, Masato;Murakami, Shuichi
我们从理论上研究了晶体中电子自旋与原子微观局部旋转之间转换的微观机制。在具有角动量的声子模式中，原子在晶体中围绕其平衡位置微观地旋转。在一个简单的带有声子的玩具模型中，我们用绝热级数展开计算了自旋期望值。我们证明了时间平均自旋磁化是由原子的微观局部旋转通过自旋轨道相互作用产生的。另一方面，在具有简单原子振动的系统中，由于时间反转对称性，时间平均自旋磁化变为零。此外，时间平均自旋磁化强度的大小取决于瞬时本征能差的倒数，并且我们表明，在带绝缘体中，随着间隙的增大，它变得更小。
We theoretically investigate the microscopic mechanism of conversion between the electron spin and the microscopic local rotation of atoms in crystals. In phonon modes with angular momenta, the atoms microscopically rotate around their equilibrium positions in crystals. In a simple toy model with phonons, we calculate the spin expectation value by using the adiabatic series expansion. We show that the time-averaged spin magnetization is generated by the microscopic local rotation of atoms via the spin-orbit interaction. On the other hand, in the system with a simple vibration of atoms, time-averaged spin magnetization becomes zero due to the time-reversal symmetry. Moreover, the magnitude of the time-averaged spin magnetization depends on the inverse of the difference of instantaneous eigenenergy, and we show that it becomes smaller in band insulators with a larger gap.