Sim Kyung Ik, Park Byung Cheol, Kim Taesoo, Cho Byeong Wook, Kim Jae Hoon, Choi Eun-Mi, Lee Young Hee
Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.
Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.
Adv Mater. 2025 Feb;37(8):e2413484. doi: 10.1002/adma.202413484. Epub 2025 Jan 8.
Research on manipulating materials using light has garnered significant interest, yet examples of controlling electronic polarization in magnetic materials remain scarce. Here, the hysteresis of electronic polarization in the anti-ferromagnetic semiconductor FePS is demonstrated via light. Below the Néel temperature, linear dichroism (i.e., optical anisotropy) without structural symmetry breaking is observed. Light-induced net polarization aligns along the a-axis (zigzag direction) at 1.6 eV due to the dipolar polarization and along the b-axis (armchair direction) at 2.0 eV due to the combined effects of dipolar and octupolar polarizations, resulting from charge transfer from the armchair to the zigzag direction by light. Unexpected hysteresis of the electronic polarization occurs at 2.0 eV due to the octupolar polarization, in contrast to the absence of such hysteresis at 1.6 eV. This is attributed to a symmetry breaking of the light-induced phase of FePS involving electronic polarization within the spin lattice. Here a new mechanism is suggested for generating and controlling electronic polarization in magnetic materials using light, with implications for future device applications.
利用光来操控材料的研究已引起了广泛关注，然而在磁性材料中控制电子极化的实例仍然很少。在此，通过光展示了反铁磁半导体FePS中电子极化的滞后现象。在奈尔温度以下，观察到了没有结构对称性破缺的线性二向色性（即光学各向异性）。由于偶极极化，光诱导的净极化在1.6电子伏特时沿a轴（之字形方向）排列，而在2.0电子伏特时，由于偶极和八极极化的综合作用，沿b轴（扶手椅方向）排列，这是由光引起的电荷从扶手椅方向转移到之字形方向所致。与1.6电子伏特时不存在这种滞后现象相反，由于八极极化，电子极化在2.0电子伏特时出现了意想不到的滞后现象。这归因于FePS的光诱导相的对称性破缺，该相涉及自旋晶格内的电子极化。本文提出了一种利用光在磁性材料中产生和控制电子极化的新机制，这对未来的器件应用具有重要意义。
