Han Seungyun, Lee Hyun-Woo, Kim Kyoung-Whan
Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea.
Center for Spintronics, Korea Institute of Science and Technology, Seoul 02792, Korea.
Phys Rev Lett. 2022 Apr 29;128(17):176601. doi: 10.1103/PhysRevLett.128.176601.
Orbital dynamics in time-reversal-symmetric centrosymmetric systems is examined theoretically. Contrary to common belief, we demonstrate that many aspects of orbital dynamics are qualitatively different from spin dynamics because the algebraic properties of the orbital and spin angular momentum operators are different. This difference generates interesting orbital responses, which do not have spin counterparts. For instance, the orbital angular momentum expectation values may oscillate even without breaking neither the time-reversal nor the inversion symmetry. Our quantum Boltzmann approach reproduces the previous result on the orbital Hall effect and reveals additional orbital dynamics phenomena, whose detection schemes are discussed briefly. Our work will be useful for the experimental differentiation of the orbital dynamics from the spin dynamics.
本文从理论上研究了时间反演对称中心对称系统中的轨道动力学。与普遍看法相反，我们证明了轨道动力学的许多方面在性质上不同于自旋动力学，因为轨道角动量算符和自旋角动量算符的代数性质不同。这种差异产生了有趣的轨道响应，而这些响应没有自旋对应物。例如，即使在不破坏时间反演对称性和空间反演对称性的情况下，轨道角动量期望值也可能振荡。我们的量子玻尔兹曼方法重现了先前关于轨道霍尔效应的结果，并揭示了额外的轨道动力学现象，文中还简要讨论了这些现象的检测方案。我们的工作将有助于从实验上区分轨道动力学和自旋动力学。
