Li Ni, Lee Hyeon Jun, Sri Gyan Deepankar, Ahn Youngjun, Landahl Eric C, Carnis Jerome, Lee Jun Young, Kim Tae Yeon, Unithrattil Sanjith, Jo Ji Young, Chun Sae Hwan, Kim Sunam, Park Sang-Youn, Eom Intae, Adamo Carolina, Li Sabrina J, Kaaret Jeffrey Z, Schlom Darrell G, Wen Haidan, Benedek Nicole A, Evans Paul G
Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
Department of Materials Science and Engineering, Kangwon National University, Samcheok 25913, South Korea.
Nano Lett. 2024 May 29;24(21):6417-6424. doi: 10.1021/acs.nanolett.4c01519. Epub 2024 May 6.
The functional properties of complex oxides, including magnetism and ferroelectricity, are closely linked to subtle structural distortions. Ultrafast optical excitations provide the means to manipulate structural features and ultimately to affect the functional properties of complex oxides with picosecond-scale precision. We report that the lattice expansion of multiferroic BiFeO following above-bandgap optical excitation leads to distortion of the oxygen octahedral rotation (OOR) pattern. The continuous coupling between OOR and strain was probed using time-resolved X-ray free-electron laser diffraction with femtosecond time resolution. Density functional theory calculations predict a relationship between the OOR and the elastic strain consistent with the experiment, demonstrating a route to employing this approach in a wider range of systems. Ultrafast control of the functional properties of BiFeO thin films is enabled by this approach because the OOR phenomena are related to ferroelectricity, and via the Fe-O-Fe bond angles, the superexchange interaction between Fe atoms.
包括磁性和铁电性在内的复合氧化物的功能特性与细微的结构畸变密切相关。超快光学激发提供了操纵结构特征并最终以皮秒级精度影响复合氧化物功能特性的手段。我们报道，多铁性BiFeO在带隙以上光学激发后晶格膨胀导致氧八面体旋转（OOR）模式畸变。利用具有飞秒时间分辨率的时间分辨X射线自由电子激光衍射探测了OOR与应变之间的连续耦合。密度泛函理论计算预测了OOR与弹性应变之间与实验一致的关系，证明了在更广泛的系统中采用这种方法的途径。这种方法能够实现对BiFeO薄膜功能特性的超快控制，因为OOR现象与铁电性有关，并且通过Fe-O-Fe键角与Fe原子之间的超交换相互作用有关。
