Giant Photostriction in Perovskite SrIrO₃ Thin Films
Yi-De Liou1*, Wen-Yen Tzeng2, Heng-Jui Liu3, Chih-Wei Luo2, Yi-Chun Chen1, Ying-Hao Chu4, Jan-Chi Yang1
1Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
2Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan
3Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan
4Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan
* Presenter:Yi-De Liou,
Photostrictive effect depicts a direct light-matter interaction that exhibits a reversible mechanical deformation in a material under light illumination. Materials which possess photostrictive characteristic are good candidates for next-generation energy conversion systems, offering gifted potential towards novel optoelectronic devices. But in reality, the small light-induced size changes in most of reported photostrictive materials cloud the prospects of practical applications. In this study, we investigated the giant visible-light-induced deformation of complex oxide SrIrO₃ (SIO), taking advantages of its strong spin-orbit coupling, sizable crystal field and high absorption across the visible spectrum at room temperature. By employing highly structural sensitive and contactless in-situ Raman spectroscopy, the red-shift behaviors of all the peaks in SIO Raman spectrum were observed with the increase of excitation laser intensities. The local strain states of SIO under laser illumination were analyzed by means of the phonon deformation potential theory. The vibrational symmetry of SIO phonon mode was revealed by group theory analysis and the lattice-mismatch-induced Raman shifts were used to calculate the phonon deformation potential coefficients. In this work, a giant photon-induced strain in SIO thin films was unveiled after deducting the local heating effect by considering the Stokes/anti-Stokes Raman intensity ratio. We found that SIO shows significant photostriction compared to conventional semiconductors, polymers and perovskite oxides under the same experiment configuration. Moreover, the fatigue characteristic hasn’t emerged under a spectrum of cyclic light illumination. The strong photostrictive effect and stability of SIO at room temperature paves a promising route towards new applications and multifunctionalities of photon-driven devices.

Keywords: photostrictive material, Raman spectroscopy, optical phonon , light-induced strain, multifunctional materials