Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
Department of Physics, Harvard University, Cambridge, MA, USA.
Nat Mater. 2023 May;22(5):583-590. doi: 10.1038/s41563-023-01493-5. Epub 2023 Mar 9.
Using circularly polarized light to control quantum matter is a highly intriguing topic in physics, chemistry and biology. Previous studies have demonstrated helicity-dependent optical control of chirality and magnetization, with important implications in asymmetric synthesis in chemistry; homochirality in biomolecules; and ferromagnetic spintronics. We report the surprising observation of helicity-dependent optical control of fully compensated antiferromagnetic order in two-dimensional even-layered MnBiTe, a topological axion insulator with neither chirality nor magnetization. To understand this control, we study an antiferromagnetic circular dichroism, which appears only in reflection but is absent in transmission. We show that the optical control and circular dichroism both arise from the optical axion electrodynamics. Our axion induction provides the possibility to optically control a family of [Formula: see text]-symmetric antiferromagnets ([Formula: see text], inversion; [Formula: see text], time-reversal) such as CrO, even-layered CrI and possibly the pseudo-gap state in cuprates. In MnBiTe, this further opens the door for optical writing of a dissipationless circuit formed by topological edge states.
利用圆偏振光控制量子物质是物理学、化学和生物学中一个非常有趣的课题。先前的研究已经证明了手性和磁化强度的螺旋相关光学控制，这在化学中的不对称合成、生物分子中的同手性以及铁磁自旋电子学方面具有重要意义。我们报告了一个令人惊讶的观察结果，即在二维偶数层 MnBiTe 中，完全补偿的反铁磁序表现出螺旋相关的光控，MnBiTe 是一种具有非手性和非磁化的拓扑轴子绝缘体。为了理解这种控制，我们研究了一种反铁磁共振圆二色性，它只出现在反射中而在透射中不存在。我们表明，光控和圆二色性都源于光轴动力学。我们的轴子感应为光学控制一族[公式：见文本]-对称反铁磁体（[公式：见文本]，反转；[公式：见文本]，时间反转）提供了可能性，如 CrO、偶数层 CrI 以及可能的铜酸盐中的赝能隙态。在 MnBiTe 中，这进一步为由拓扑边缘态形成的无耗散电路的光学写入开辟了道路。
